Merge remote-tracking branch 'origin/dmw'

* origin/dmw:
  tests: add new compression parameter to mitogen_get_stack results
  tests: disable affinity_test on Travis :/
  issue #508: fix responder stats test due to new smaller parent.py.
  issue #508: tests: skip minify_test Py2.4/2.5 for profiler.py.
  tests: fix fallout from 36fb318adf5c56e729296c3efce84f4dd75ced4e
  issue #520: add AIX auth failure string to su.
  tests: move affinity_test to Ansible tests.
  core: cProfile is not available in 2.4.
  issue #505: docs: add new detail graph for one scenario.
  docs: update and re-record profile graphs in docs; closes #505
  service: fix PushFileService exception
  tests: pad out localhost-*
  service: start pool shutdown on broker shutdown.
  master: .encode() needed for Py3.
  ansible: stash PID files in CWD if requested for debugging.
  issue #508: master: minify_safe_re must be bytes for Py3.
  bench: tidy up and cpu-pin some more files.
  tests: add localhost-x100
  ansible: double the default pool size.
  ansible: raise error with correct exception type.
  issue #508: master: minify all Mitogen/ansible_mitogen sources.
  parent: PartialZlib docstrings.
  ansible: hacky parser to alow bools to be specified on command line
  parent: pre-cache bootstrap if possible.
  docs: update Changelog.
  ansible: add mitogen_ssh_compression variable.
  service: PushFileService never recorded a file as sent.
  parent: synchronize get_core_source()
  service: use correct profile aggregation name.
  SyntaxError.
  ansible: don't pin controller if <4 cores.
  tests: make soak testing work reliably on vanilla.
  docs: changelog tidyups.
  ansible: document and make affinity stuff portable to non-Linux
  ansible: fix affinity.py test failure on 2 cores.
  ansible: preheat PluginLoader caches before fork.
  tests: make mitogen_shutdown_all be run_once by default.
  docs: update Changelog.
  ansible: use Poller for WorkerProcess; closes #491.
  ansible: new multiplexer/workers configuration
  docs: update Changelog.
  docs: update Changelog.
  ansible: pin connection multiplexer to a single core
  utils: pad out reset_affinity() and integrate with detach_popen()
  utils: import reset_affinity() function.
  master: set Router.profiling if MITOGEN_PROFILING variable present.
  parent: don't kill children when profiling is active.
  ansible: hook strategy and worker processes into profiler
  profiler: import from linear2 branch
  core: tidy up existing profiling code and support MITOGEN_PROFILE_FMT
  issue #260: redundant if statement.
  ansible: ensure MuxProcess MITOGEN_PROFILING results reach disk.
  ansible/bench: make end= configurable.
  master: cache sent/forwarded module names

ansible_mitogen/affinity.py

@@ -0,0 +1,241 @@
+# Copyright 2017, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+"""
+As Mitogen separates asynchronous IO out to a broker thread, communication
+necessarily involves context switching and waking that thread. When application
+threads and the broker share a CPU, this can be almost invisibly fast - around
+25 microseconds for a full A->B->A round-trip.
+
+However when threads are scheduled on different CPUs, round-trip delays
+regularly vary wildly, and easily into milliseconds. Many contributing factors
+exist, not least scenarios like:
+
+1. A is preempted immediately after waking B, but before releasing the GIL.
+2. B wakes from IO wait only to immediately enter futex wait.
+3. A may wait 10ms or more for another timeslice, as the scheduler on its CPU
+   runs threads unrelated to its transaction (i.e. not B), wake only to release
+   its GIL, before entering IO sleep waiting for a reply from B, which cannot
+   exist yet.
+4. B wakes, acquires GIL, performs work, and sends reply to A, causing it to
+   wake. B is preempted before releasing GIL.
+5. A wakes from IO wait only to immediately enter futex wait.
+6. B may wait 10ms or more for another timeslice, wake only to release its GIL,
+   before sleeping again.
+7. A wakes, acquires GIL, finally receives reply.
+
+Per above if we are unlucky, on an even moderately busy machine it is possible
+to lose milliseconds just in scheduling delay, and the effect is compounded
+when pairs of threads in process A are communicating with pairs of threads in
+process B using the same scheme, such as when Ansible WorkerProcess is
+communicating with ContextService in the connection multiplexer. In the worst
+case it could involve 4 threads working in lockstep spread across 4 busy CPUs.
+
+Since multithreading in Python is essentially useless except for waiting on IO
+due to the presence of the GIL, at least in Ansible there is no good reason for
+threads in the same process to run on distinct CPUs - they always operate in
+lockstep due to the GIL, and are thus vulnerable to issues like above.
+
+Linux lacks any natural API to describe what we want, it only permits
+individual threads to be constrained to run on specific CPUs, and for that
+constraint to be inherited by new threads and forks of the constrained thread.
+
+This module therefore implements a CPU pinning policy for Ansible processes,
+providing methods that should be called early in any new process, either to
+rebalance which CPU it is pinned to, or in the case of subprocesses, to remove
+the pinning entirely. It is likely to require ongoing tweaking, since pinning
+necessarily involves preventing the scheduler from making load balancing
+decisions.
+"""
+
+import ctypes
+import mmap
+import multiprocessing
+import os
+import struct
+
+import mitogen.parent
+
+
+try:
+    _libc = ctypes.CDLL(None, use_errno=True)
+    _strerror = _libc.strerror
+    _strerror.restype = ctypes.c_char_p
+    _pthread_mutex_init = _libc.pthread_mutex_init
+    _pthread_mutex_lock = _libc.pthread_mutex_lock
+    _pthread_mutex_unlock = _libc.pthread_mutex_unlock
+    _sched_setaffinity = _libc.sched_setaffinity
+except (OSError, AttributeError):
+    _libc = None
+    _strerror = None
+    _pthread_mutex_init = None
+    _pthread_mutex_lock = None
+    _pthread_mutex_unlock = None
+    _sched_setaffinity = None
+
+
+class pthread_mutex_t(ctypes.Structure):
+    """
+    Wrap pthread_mutex_t to allow storing a lock in shared memory.
+    """
+    _fields_ = [
+        ('data', ctypes.c_uint8 * 512),
+    ]
+
+    def init(self):
+        if _pthread_mutex_init(self.data, 0):
+            raise Exception(_strerror(ctypes.get_errno()))
+
+    def acquire(self):
+        if _pthread_mutex_lock(self.data):
+            raise Exception(_strerror(ctypes.get_errno()))
+
+    def release(self):
+        if _pthread_mutex_unlock(self.data):
+            raise Exception(_strerror(ctypes.get_errno()))
+
+
+class State(ctypes.Structure):
+    """
+    Contents of shared memory segment. This allows :meth:`Manager.assign` to be
+    called from any child, since affinity assignment must happen from within
+    the context of the new child process.
+    """
+    _fields_ = [
+        ('lock', pthread_mutex_t),
+        ('counter', ctypes.c_uint8),
+    ]
+
+
+class Policy(object):
+    """
+    Process affinity policy.
+    """
+    def assign_controller(self):
+        """
+        Assign the Ansible top-level policy to this process.
+        """
+
+    def assign_muxprocess(self):
+        """
+        Assign the MuxProcess policy to this process.
+        """
+
+    def assign_worker(self):
+        """
+        Assign the WorkerProcess policy to this process.
+        """
+
+    def assign_subprocess(self):
+        """
+        Assign the helper subprocess policy to this process.
+        """
+
+
+class LinuxPolicy(Policy):
+    """
+    :class:`Policy` for Linux machines. The scheme here was tested on an
+    otherwise idle 16 thread machine.
+
+    - The connection multiplexer is pinned to CPU 0.
+    - The Ansible top-level (strategy) is pinned to CPU 1.
+    - WorkerProcesses are pinned sequentually to 2..N, wrapping around when no
+      more CPUs exist.
+    - Children such as SSH may be scheduled on any CPU except 0/1.
+
+    If the machine has less than 4 cores available, the top-level and workers
+    are pinned between CPU 2..N, i.e. no CPU is reserved for the top-level
+    process.
+
+    This could at least be improved by having workers pinned to independent
+    cores, before reusing the second hyperthread of an existing core.
+
+    A hook is installed that causes :meth:`reset` to run in the child of any
+    process created with :func:`mitogen.parent.detach_popen`, ensuring
+    CPU-intensive children like SSH are not forced to share the same core as
+    the (otherwise potentially very busy) parent.
+    """
+    def __init__(self):
+        self.mem = mmap.mmap(-1, 4096)
+        self.state = State.from_buffer(self.mem)
+        self.state.lock.init()
+        if self._cpu_count() < 4:
+            self._reserve_mask = 3
+            self._reserve_shift = 2
+            self._reserve_controller = True
+        else:
+            self._reserve_mask = 1
+            self._reserve_shift = 1
+            self._reserve_controller = False
+
+    def _set_affinity(self, mask):
+        mitogen.parent._preexec_hook = self._clear
+        s = struct.pack('L', mask)
+        _sched_setaffinity(os.getpid(), len(s), s)
+
+    def _cpu_count(self):
+        return multiprocessing.cpu_count()
+
+    def _balance(self):
+        self.state.lock.acquire()
+        try:
+            n = self.state.counter
+            self.state.counter += 1
+        finally:
+            self.state.lock.release()
+
+        self._set_cpu(self._reserve_shift + (
+            (n % max(1, (self._cpu_count() - self._reserve_shift)))
+        ))
+
+    def _set_cpu(self, cpu):
+        self._set_affinity(1 << cpu)
+
+    def _clear(self):
+        self._set_affinity(0xffffffff & ~self._reserve_mask)
+
+    def assign_controller(self):
+        if self._reserve_controller:
+            self._set_cpu(1)
+        else:
+            self._balance()
+
+    def assign_muxprocess(self):
+        self._set_cpu(0)
+
+    def assign_worker(self):
+        self._balance()
+
+    def assign_subprocess(self):
+        self._clear()
+
+
+if _sched_setaffinity is not None:
+    policy = LinuxPolicy()
+else:
+    policy = Policy()

ansible_mitogen/connection.py

@@ -44,6 +44,7 @@ import ansible.errors
 import ansible.plugins.connection
 import ansible.utils.shlex
 
+import mitogen.core
 import mitogen.fork
 import mitogen.unix
 import mitogen.utils
@@ -69,6 +70,27 @@ def optional_int(value):
         return None
 
 
+def convert_bool(obj):
+    if isinstance(obj, bool):
+        return obj
+    if str(obj).lower() in ('no', 'false', '0'):
+        return False
+    if str(obj).lower() not in ('yes', 'true', '1'):
+        raise ansible.errors.AnsibleConnectionFailure(
+            'expected yes/no/true/false/0/1, got %r' % (obj,)
+        )
+    return True
+
+
+def default(value, default):
+    """
+    Return `default` is `value` is :data:`None`, otherwise return `value`.
+    """
+    if value is None:
+        return default
+    return value
+
+
 def _connect_local(spec):
     """
     Return ContextService arguments for a local connection.
@@ -102,6 +124,9 @@ def _connect_ssh(spec):
             'check_host_keys': check_host_keys,
             'hostname': spec.remote_addr(),
             'username': spec.remote_user(),
+            'compression': convert_bool(
+                default(spec.mitogen_ssh_compression(), True)
+            ),
             'password': spec.password(),
             'port': spec.port(),
             'python_path': spec.python_path(),
@@ -340,12 +365,21 @@ CONNECTION_METHOD = {
 }
 
 
+class Broker(mitogen.master.Broker):
+    """
+    WorkerProcess maintains at most 2 file descriptors, therefore does not need
+    the exuberant syscall expense of EpollPoller, so override it and restore
+    the poll() poller.
+    """
+    poller_class = mitogen.core.Poller
+
+
 class CallChain(mitogen.parent.CallChain):
     """
     Extend :class:`mitogen.parent.CallChain` to additionally cause the
     associated :class:`Connection` to be reset if a ChannelError occurs.
 
-    This only catches failures that occur while a call is pnding, it is a
+    This only catches failures that occur while a call is pending, it is a
     stop-gap until a more general method is available to notice connection in
     every situation.
     """

ansible_mitogen/process.py

@@ -56,6 +56,7 @@ import ansible_mitogen.logging
 import ansible_mitogen.services
 
 from mitogen.core import b
+import ansible_mitogen.affinity
 
 
 LOG = logging.getLogger(__name__)
@@ -93,6 +94,24 @@ def getenv_int(key, default=0):
         return default
 
 
+def save_pid(name):
+    """
+    When debugging and profiling, it is very annoying to poke through the
+    process list to discover the currently running Ansible and MuxProcess IDs,
+    especially when trying to catch an issue during early startup. So here, if
+    a magic environment variable set, stash them in hidden files in the CWD::
+
+        alias muxpid="cat .ansible-mux.pid"
+        alias anspid="cat .ansible-controller.pid"
+
+        gdb -p $(muxpid)
+        perf top -p $(anspid)
+    """
+    if os.environ.get('MITOGEN_SAVE_PIDS'):
+        with open('.ansible-%s.pid' % (name,), 'w') as fp:
+            fp.write(str(os.getpid()))
+
+
 class MuxProcess(object):
     """
     Implement a subprocess forked from the Ansible top-level, as a safe place
@@ -163,7 +182,8 @@ class MuxProcess(object):
         mitogen.core.set_cloexec(cls.worker_sock.fileno())
         mitogen.core.set_cloexec(cls.child_sock.fileno())
 
-        if os.environ.get('MITOGEN_PROFILING'):
+        cls.profiling = os.environ.get('MITOGEN_PROFILING') is not None
+        if cls.profiling:
             mitogen.core.enable_profiling()
 
         cls.original_env = dict(os.environ)
@@ -171,10 +191,14 @@ class MuxProcess(object):
         if _init_logging:
             ansible_mitogen.logging.setup()
         if cls.child_pid:
+            save_pid('controller')
+            ansible_mitogen.affinity.policy.assign_controller()
             cls.child_sock.close()
             cls.child_sock = None
             mitogen.core.io_op(cls.worker_sock.recv, 1)
         else:
+            save_pid('mux')
+            ansible_mitogen.affinity.policy.assign_muxprocess()
             cls.worker_sock.close()
             cls.worker_sock = None
             self = cls()
@@ -270,7 +294,7 @@ class MuxProcess(object):
                 ansible_mitogen.services.ContextService(self.router),
                 ansible_mitogen.services.ModuleDepService(self.router),
             ],
-            size=getenv_int('MITOGEN_POOL_SIZE', default=16),
+            size=getenv_int('MITOGEN_POOL_SIZE', default=32),
         )
         LOG.debug('Service pool configured: size=%d', self.pool.size)
 
@@ -281,7 +305,9 @@ class MuxProcess(object):
         then cannot clean up pending handlers, which is required for the
         threads to exit gracefully.
         """
-        self.pool.stop(join=False)
+        # In normal operation we presently kill the process because there is
+        # not yet any way to cancel connect().
+        self.pool.stop(join=self.profiling)
 
     def on_broker_exit(self):
         """
@@ -289,10 +315,9 @@ class MuxProcess(object):
         ourself. In future this should gracefully join the pool, but TERM is
         fine for now.
         """
-        if os.environ.get('MITOGEN_PROFILING'):
-            # TODO: avoid killing pool threads before they have written their
-            # .pstats. Really shouldn't be using kill() here at all, but hard
-            # to guarantee services can always be unblocked during shutdown.
-            time.sleep(1)
-
+        if not self.profiling:
+            # In normal operation we presently kill the process because there is
+            # not yet any way to cancel connect(). When profiling, threads
+            # including the broker must shut down gracefully, otherwise pstats
+            # won't be written.
             os.kill(os.getpid(), signal.SIGTERM)

ansible_mitogen/runner.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 These classes implement execution for each style of Ansible module. They are
 instantiated in the target context by way of target.py::run_module().

ansible_mitogen/services.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 Classes in this file define Mitogen 'services' that run (initially) within the
 connection multiplexer process that is forked off the top-level controller

ansible_mitogen/strategy.py

@@ -28,12 +28,17 @@
 
 from __future__ import absolute_import
 import os
+import signal
 import threading
 
+import mitogen.core
+import ansible_mitogen.affinity
 import ansible_mitogen.loaders
 import ansible_mitogen.mixins
 import ansible_mitogen.process
 
+import ansible.executor.process.worker
+
 
 def _patch_awx_callback():
     """
@@ -93,6 +98,22 @@ def wrap_connection_loader__get(name, *args, **kwargs):
     return connection_loader__get(name, *args, **kwargs)
 
 
+def wrap_worker__run(*args, **kwargs):
+    """
+    While the strategy is active, rewrite connection_loader.get() calls for
+    some transports into requests for a compatible Mitogen transport.
+    """
+    # Ignore parent's attempts to murder us when we still need to write
+    # profiling output.
+    if mitogen.core._profile_hook.__name__ != '_profile_hook':
+        signal.signal(signal.SIGTERM, signal.SIG_IGN)
+
+    ansible_mitogen.affinity.policy.assign_worker()
+    return mitogen.core._profile_hook('WorkerProcess',
+        lambda: worker__run(*args, **kwargs)
+    )
+
+
 class StrategyMixin(object):
     """
     This mix-in enhances any built-in strategy by arranging for various Mitogen
@@ -167,12 +188,17 @@ class StrategyMixin(object):
         connection_loader__get = ansible_mitogen.loaders.connection_loader.get
         ansible_mitogen.loaders.connection_loader.get = wrap_connection_loader__get
 
+        global worker__run
+        worker__run = ansible.executor.process.worker.WorkerProcess.run
+        ansible.executor.process.worker.WorkerProcess.run = wrap_worker__run
+
     def _remove_wrappers(self):
         """
         Uninstall the PluginLoader monkey patches.
         """
         ansible_mitogen.loaders.action_loader.get = action_loader__get
         ansible_mitogen.loaders.connection_loader.get = connection_loader__get
+        ansible.executor.process.worker.WorkerProcess.run = worker__run
 
     def _add_plugin_paths(self):
         """
@@ -187,15 +213,44 @@ class StrategyMixin(object):
             os.path.join(base_dir, 'action')
         )
 
+    def _queue_task(self, host, task, task_vars, play_context):
+        """
+        Many PluginLoader caches are defective as they are only populated in
+        the ephemeral WorkerProcess. Touch each plug-in path before forking to
+        ensure all workers receive a hot cache.
+        """
+        ansible_mitogen.loaders.module_loader.find_plugin(
+            name=task.action,
+            mod_type='',
+        )
+        ansible_mitogen.loaders.connection_loader.get(
+            name=play_context.connection,
+            class_only=True,
+        )
+        ansible_mitogen.loaders.action_loader.get(
+            name=task.action,
+            class_only=True,
+        )
+
+        return super(StrategyMixin, self)._queue_task(
+            host=host,
+            task=task,
+            task_vars=task_vars,
+            play_context=play_context,
+        )
+
     def run(self, iterator, play_context, result=0):
         """
         Arrange for a mitogen.master.Router to be available for the duration of
         the strategy's real run() method.
         """
         ansible_mitogen.process.MuxProcess.start()
+        run = super(StrategyMixin, self).run
         self._add_plugin_paths()
         self._install_wrappers()
         try:
-            return super(StrategyMixin, self).run(iterator, play_context)
+            return mitogen.core._profile_hook('Strategy',
+                lambda: run(iterator, play_context)
+            )
         finally:
             self._remove_wrappers()

ansible_mitogen/target.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 Helper functions intended to be executed on the target. These are entrypoints
 for file transfer, module execution and sundry bits like changing file modes.

ansible_mitogen/transport_config.py

@@ -273,6 +273,12 @@ class Spec(with_metaclass(abc.ABCMeta, object)):
         The SSH debug level.
         """
 
+    @abc.abstractmethod
+    def mitogen_ssh_compression(self):
+        """
+        Whether SSH compression is enabled.
+        """
+
     @abc.abstractmethod
     def extra_args(self):
         """
@@ -398,6 +404,9 @@ class PlayContextSpec(Spec):
     def mitogen_ssh_debug_level(self):
         return self._connection.get_task_var('mitogen_ssh_debug_level')
 
+    def mitogen_ssh_compression(self):
+        return self._connection.get_task_var('mitogen_ssh_compression')
+
     def extra_args(self):
         return self._connection.get_extra_args()
 
@@ -577,5 +586,8 @@ class MitogenViaSpec(Spec):
     def mitogen_ssh_debug_level(self):
         return self._host_vars.get('mitogen_ssh_debug_level')
 
+    def mitogen_ssh_compression(self):
+        return self._host_vars.get('mitogen_ssh_compression')
+
     def extra_args(self):
         return []  # TODO

docs/ansible.rst

@@ -179,7 +179,7 @@ Noteworthy Differences
   practice, and light web searches failed to reveal many examples of them.
 
 * Ansible permits up to ``forks`` connections to be setup in parallel, whereas
-  in Mitogen this is handled by a fixed-size thread pool. Up to 16 connections
+  in Mitogen this is handled by a fixed-size thread pool. Up to 32 connections
   may be established in parallel by default, this can be modified by setting
   the ``MITOGEN_POOL_SIZE`` environment variable.
 
@@ -901,6 +901,10 @@ except connection delegation is supported.
 * ``ssh_args``, ``ssh_common_args``, ``ssh_extra_args``
 * ``mitogen_ssh_debug_level``: integer between `0..3` indicating the SSH client
   debug level. Ansible must also be run with '-vvv' to view the output.
+* ``mitogen_ssh_compression``: :data:`True` to enable SSH compression,
+  otherwise :data:`False`. This will change to off by default in a future
+  release. If you are targetting many hosts on a fast network, please consider
+  disabling SSH compression.
 
 
 Debugging
@@ -1164,35 +1168,103 @@ FreeNode IRC network.
 Sample Profiles
 ---------------
 
-Local VM connection
-~~~~~~~~~~~~~~~~~~~
+The summaries below may be reproduced using data and scripts maintained in the
+`pcaps branch <https://github.com/dw/mitogen/tree/pcaps/>`_. Traces were
+recorded using Ansible 2.5.14.
+
+
+Trivial Loop: Local Host
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+This demonstrates Mitogen vs. SSH pipelining to the local machine running
+`bench/loop-100-items.yml
+<https://github.com/dw/mitogen/blob/master/tests/ansible/bench/loop-100-items.yml>`_,
+executing a simple command 100 times. Most Ansible controller overhead is
+isolated, characterizing just module executor and connection layer performance.
+Mitogen requires **63x less bandwidth and 5.9x less time**.
+
+.. image:: images/ansible/pcaps/loop-100-items-local.svg
+
+Unlike in SSH pipelining where payloads are sent as a single compressed block,
+by default Mitogen enables SSH compression for its uncompressed RPC data. In
+many-host scenarios it may be desirable to disable compression. This has
+negligible impact on footprint, since program code is separately compressed and
+sent only once. Compression also benefits SSH pipelining, but the presence of
+large precompressed per-task payloads may present a more significant CPU burden
+during many-host runs.
+
+.. image:: images/ansible/pcaps/loop-100-items-local-detail.svg
+
+In a detailed trace, improved interaction with the host machine is visible. In
+this playbook because no forks were required to start SSH clients from the
+worker process executing the loop, the worker's memory was never marked
+read-only, thus avoiding a major hidden performance problem - the page fault
+rate is more than halved.
+
+
+File Transfer: UK to France
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+`This playbook
+<https://github.com/dw/mitogen/blob/master/tests/ansible/regression/issue_140__thread_pileup.yml>`_
+was used to compare file transfer performance over a ~26 ms link. It uses the
+``with_filetree`` loop syntax to copy a directory of 1,000 0-byte files to the
+target.
 
-This demonstrates Mitogen vs. connection pipelining to a local VM executing
-``bench/loop-100-items.yml``, which simply executes ``hostname`` 100 times.
-Mitogen requires **43x less bandwidth and 6.5x less time**.
+.. raw:: html
+
+    <style>
+        .nojunk td,
+        .nojunk th { padding: 4px; font-size: 90%; text-align: right !important; }
+
+        table.docutils col {
+            width: auto !important;
+        }
+    </style>
+
+.. csv-table::
+    :header: , Secs, CPU Secs, Sent, Received, Roundtrips
+    :class: nojunk
+    :align: right
+
+    Mitogen, 98.54, 43.04, "815 KiB", "447 KiB", 3.79
+    SSH Pipelining, "1,483.54", 329.37, "99,539 KiB", "6,870 KiB", 57.01
+
+*Roundtrips* is the approximate number of network roundtrips required to
+describe the runtime that was consumed. Due to Mitogen's built-in file transfer
+support, continuous reinitialization of an external `scp`/`sftp` client is
+avoided, permitting large ``with_filetree`` copies to become practical without
+any special casing within the playbook or the Ansible implementation.
+
+
+DebOps: UK to India
+~~~~~~~~~~~~~~~~~~~
 
-.. image:: images/ansible/run_hostname_100_times_mito.svg
-.. image:: images/ansible/run_hostname_100_times_plain.svg
+This is an all-green run of 246 tasks from the `DebOps
+<https://docs.debops.org/en/master/>`_ 0.7.2 `common.yml
+<https://github.com/debops/debops-playbooks/blob/master/playbooks/common.yml>`_
+playbook over a ~370 ms link between the UK and India. The playbook touches a
+wide variety of modules, many featuring unavoidable waits for slow computation
+on the target.
 
+More tasks of a wider variety are featured than previously, placing strain on
+Mitogen's module loading and in-memory caching. By running over a long-distance
+connection, it highlights behaviour of the connection layer in the presence of
+high latency.
 
-Kathmandu to Paris
-~~~~~~~~~~~~~~~~~~
+Mitogen requires **14.5x less bandwidth and 4x less time**.
 
-This is a full Django application playbook over a ~180ms link between Kathmandu
-and Paris. Aside from large pauses where the host performs useful work, the
-high latency of this link means Mitogen only manages a 1.7x speedup.
+.. image:: images/ansible/pcaps/debops-uk-india.svg
 
-Many early roundtrips are due to inefficiencies in Mitogen's importer that will
-be fixed over time, however the majority, comprising at least 10 seconds, are
-due to idling while the host's previous result and next command are in-flight
-on the network.
 
-The initial extension lays groundwork for exciting structural changes to the
-execution model: a future version will tackle latency head-on by delegating
-some control flow to the target host, melding the performance and scalability
-benefits of pull-based operation with the management simplicity of push-based
-operation.
+Django App: UK to India
+~~~~~~~~~~~~~~~~~~~~~~~
 
-.. image:: images/ansible/costapp.png
+This short playbook features only 23 steps executed over the same ~370 ms link
+as previously, with many steps running unavoidably expensive tasks like
+building C++ code, and compiling static web site assets.
 
+Despite the small margin for optimization, Mitogen still manages **6.2x less
+bandwidth and 1.8x less time**.
 
+.. image:: images/ansible/pcaps/costapp-uk-india.svg

docs/changelog.rst

@@ -131,6 +131,10 @@ v0.2.4 (2018-??-??)
 Mitogen for Ansible
 ~~~~~~~~~~~~~~~~~~~
 
+This release includes a huge variety of important fixes and new optimizations.
+It is 35% faster than 0.2.3 on a synthetic 64 target run that places heavy load
+on the connection multiplexer.
+
 Enhancements
 ^^^^^^^^^^^^
 
@@ -138,7 +142,7 @@ Enhancements
   `#351 <https://github.com/dw/mitogen/issues/351>`_,
   `#352 <https://github.com/dw/mitogen/issues/352>`_: disconnect propagation
   has improved, allowing Ansible to cancel waits for responses from abruptly
-  disconnected targets. This ensures a task will gracefully fail rather than
+  disconnected targets. This ensures a task will reliably fail rather than
   hang, for example on network failure or EC2 instance maintenance.
 
 * `#369 <https://github.com/dw/mitogen/issues/369>`_,
@@ -154,20 +158,6 @@ Enhancements
   ``mitogen_host_pinned`` strategy wraps the ``host_pinned`` strategy
   introduced in Ansible 2.7.
 
-* `#412 <https://github.com/dw/mitogen/issues/412>`_: to simplify diagnosing
-  issues with connection configuration, Mitogen ships with a
-  ``mitogen_get_stack`` action that is automatically added to the action
-  plug-in path. See :ref:`mitogen-get-stack` for more information.
-
-* `#415 <https://github.com/dw/mitogen/issues/415>`_,
-  `#493 <https://github.com/dw/mitogen/issues/493>`_: the interface employed
-  for in-process queues changed from `kqueue
-  <https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2>`_ / `epoll
-  <http://man7.org/linux/man-pages/man7/epoll.7.html>`_ to `poll()
-  <http://man7.org/linux/man-pages/man2/poll.2.html>`_, which requires no setup
-  or teardown, yielding a 38% latency reduction for inter-thread communication.
-  This may manifest as a runtime improvement in many-host runs.
-
 * `#477 <https://github.com/dw/mitogen/issues/477>`_: Python 2.4 is fully
   supported by the core library and tested automatically, in any parent/child
   combination of 2.4, 2.6, 2.7 and 3.6 interpreters.
@@ -178,6 +168,50 @@ Enhancements
   managed with Mitogen. The ``simplejson`` package need not be installed on
   such targets, as is usually required by Ansible.
 
+* `#412 <https://github.com/dw/mitogen/issues/412>`_: to simplify diagnosing
+  connection configuration problems, Mitogen ships a ``mitogen_get_stack``
+  action that is automatically added to the action plug-in path. See
+  :ref:`mitogen-get-stack` for more information.
+
+* `152effc2 <https://github.com/dw/mitogen/commit/152effc2>`_,
+  `bd4b04ae <https://github.com/dw/mitogen/commit/bd4b04ae>`_: a CPU affinity
+  policy was added for Linux controllers, reducing latency and SMP overhead on
+  hot paths exercised for every task. This yielded a 19% speedup in a 64-target
+  job composed of many short tasks, and should easily be visible as a runtime
+  improvement in many-host runs.
+
+* `2b44d598 <https://github.com/dw/mitogen/commit/2b44d598>`_: work around a
+  defective caching mechanism by pre-heating it before spawning workers. This
+  saves 40% runtime on a synthetic repetitive task.
+
+* `0979422a <https://github.com/dw/mitogen/commit/0979422a>`_: an expensive
+  dependency scanning step was redundantly invoked for every task,
+  bottlenecking the connection multiplexer.
+
+* `eaa990a97 <https://github.com/dw/mitogen/commit/eaa990a97>`_: a new
+  ``mitogen_ssh_compression`` variable is supported, allowing Mitogen's default
+  SSH compression to be disabled. SSH compression is a large contributor to CPU
+  usage in many-target runs, and severely limits file transfer. On a `"shell:
+  hostname"` task repeated 500 times, Mitogen requires around 800 bytes per
+  task with compression, rising to 3 KiB without. File transfer throughput
+  rises from ~25MiB/s when enabled to ~200MiB/s when disabled.
+
+* `#260 <https://github.com/dw/mitogen/issues/260>`_,
+  `a18a083c <https://github.com/dw/mitogen/commit/a18a083c>`_: brokers no
+  longer wait for readiness indication to transmit, and instead assume
+  transmission will succeed. As this is usually true, one loop iteration and
+  two poller reconfigurations are avoided, yielding a significant reduction in
+  interprocess round-trip latency.
+
+* `#415 <https://github.com/dw/mitogen/issues/415>`_,
+  `#491 <https://github.com/dw/mitogen/issues/491>`_,
+  `#493 <https://github.com/dw/mitogen/issues/493>`_: the interface employed
+  for in-process queues changed from `kqueue
+  <https://www.freebsd.org/cgi/man.cgi?query=kqueue&sektion=2>`_ / `epoll
+  <http://man7.org/linux/man-pages/man7/epoll.7.html>`_ to `poll()
+  <http://man7.org/linux/man-pages/man2/poll.2.html>`_, which requires no setup
+  or teardown, yielding a 38% latency reduction for inter-thread communication.
+
 
 Fixes
 ^^^^^
@@ -279,6 +313,10 @@ Fixes
   when starting async tasks, where it was possible for the controller to
   observe no status file on disk before the task had a chance to write one.
 
+* `2c7af9f04 <https://github.com/dw/mitogen/commit/2c7af9f04>`_: Ansible
+  modules were repeatedly re-transferred. The bug was hidden by the previously
+  mandatorily enabled SSH compression.
+
 
 Core Library
 ~~~~~~~~~~~~

docs/images/ansible/pcaps/.gitattributes

@@ -1,3 +1,3 @@
-*.pcapng filter=lfs diff=lfs merge=lfs -text
+**pcap** filter=lfs diff=lfs merge=lfs -text
 run_hostname_100_times_mito.pcap.gz filter=lfs diff=lfs merge=lfs -text
 run_hostname_100_times_vanilla.pcap.gz filter=lfs diff=lfs merge=lfs -text

docs/images/ansible/pcaps/stroke-width.py

@@ -0,0 +1,16 @@
+
+import sys
+# Add viewBox attr to SVGs lacking it, so IE scales properly.
+
+import lxml.etree
+import glob
+
+
+for name in sys.argv[1:]:  # glob.glob('*/*.svg'): #+ glob.glob('images/ansible/*.svg'):
+    doc = lxml.etree.parse(open(name))
+    svg = doc.getroot()
+    for elem in svg.cssselect('[stroke-width]'):
+        if elem.attrib['stroke-width'] < '2':
+            elem.attrib['stroke-width'] = '2'
+
+    open(name, 'w').write(lxml.etree.tostring(svg, xml_declaration=True, encoding='UTF-8'))

docs/pcaps/run_hostname_100_times_mito.pcap.gz

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:6d9b4d4ff263003bd16e44c265783e7c1deff19950e453e3adeb8a6ab5052081
-size 175120

docs/pcaps/run_hostname_100_times_vanilla.pcap.gz

@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:7a993832501b7948a38c2e8ced3467d1cb04279a57ddd6afc735ed96ec509c08
-size 7623337

mitogen/__init__.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 On the Mitogen master, this is imported from ``mitogen/__init__.py`` as would
 be expected. On the slave, it is built dynamically during startup.
@@ -57,7 +59,12 @@ parent_id = None
 parent_ids = []
 
 
-def main(log_level='INFO', profiling=False):
+import os
+_default_profiling = os.environ.get('MITOGEN_PROFILING') is not None
+del os
+
+
+def main(log_level='INFO', profiling=_default_profiling):
     """
     Convenience decorator primarily useful for writing discardable test
     scripts.
@@ -106,7 +113,7 @@ def main(log_level='INFO', profiling=False):
             mitogen.master.Router.profiling = profiling
         utils.log_to_file(level=log_level)
         return mitogen.core._profile_hook(
-            'main',
+            'app.main',
             utils.run_with_router,
             func,
         )

mitogen/compat/functools.py

@@ -1,288 +0,0 @@
-# encoding: utf-8
-"""Selected backports from Python stdlib functools module
-"""
-# Written by Nick Coghlan <ncoghlan at gmail.com>,
-# Raymond Hettinger <python at rcn.com>,
-# and Łukasz Langa <lukasz at langa.pl>.
-#   Copyright (C) 2006-2013 Python Software Foundation.
-
-__all__ = [
-    'update_wrapper', 'wraps', 'WRAPPER_ASSIGNMENTS', 'WRAPPER_UPDATES',
-    'lru_cache',
-]
-
-from threading import RLock
-
-
-################################################################################
-### update_wrapper() and wraps() decorator
-################################################################################
-
-# update_wrapper() and wraps() are tools to help write
-# wrapper functions that can handle naive introspection
-
-WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__qualname__', '__doc__',
-                       '__annotations__')
-WRAPPER_UPDATES = ('__dict__',)
-def update_wrapper(wrapper,
-                   wrapped,
-                   assigned = WRAPPER_ASSIGNMENTS,
-                   updated = WRAPPER_UPDATES):
-    """Update a wrapper function to look like the wrapped function
-       wrapper is the function to be updated
-       wrapped is the original function
-       assigned is a tuple naming the attributes assigned directly
-       from the wrapped function to the wrapper function (defaults to
-       functools.WRAPPER_ASSIGNMENTS)
-       updated is a tuple naming the attributes of the wrapper that
-       are updated with the corresponding attribute from the wrapped
-       function (defaults to functools.WRAPPER_UPDATES)
-    """
-    for attr in assigned:
-        try:
-            value = getattr(wrapped, attr)
-        except AttributeError:
-            pass
-        else:
-            setattr(wrapper, attr, value)
-    for attr in updated:
-        getattr(wrapper, attr).update(getattr(wrapped, attr, {}))
-    # Issue #17482: set __wrapped__ last so we don't inadvertently copy it
-    # from the wrapped function when updating __dict__
-    wrapper.__wrapped__ = wrapped
-    # Return the wrapper so this can be used as a decorator via partial()
-    return wrapper
-
-def wraps(wrapped,
-          assigned = WRAPPER_ASSIGNMENTS,
-          updated = WRAPPER_UPDATES):
-    """Decorator factory to apply update_wrapper() to a wrapper function
-       Returns a decorator that invokes update_wrapper() with the decorated
-       function as the wrapper argument and the arguments to wraps() as the
-       remaining arguments. Default arguments are as for update_wrapper().
-       This is a convenience function to simplify applying partial() to
-       update_wrapper().
-    """
-    return partial(update_wrapper, wrapped=wrapped,
-                   assigned=assigned, updated=updated)
-
-
-################################################################################
-### partial() argument application
-################################################################################
-
-# Purely functional, no descriptor behaviour
-def partial(func, *args, **keywords):
-    """New function with partial application of the given arguments
-    and keywords.
-    """
-    if hasattr(func, 'func'):
-        args = func.args + args
-        tmpkw = func.keywords.copy()
-        tmpkw.update(keywords)
-        keywords = tmpkw
-        del tmpkw
-        func = func.func
-
-    def newfunc(*fargs, **fkeywords):
-        newkeywords = keywords.copy()
-        newkeywords.update(fkeywords)
-        return func(*(args + fargs), **newkeywords)
-    newfunc.func = func
-    newfunc.args = args
-    newfunc.keywords = keywords
-    return newfunc
-
-
-################################################################################
-### LRU Cache function decorator
-################################################################################
-
-class _HashedSeq(list):
-    """ This class guarantees that hash() will be called no more than once
-        per element.  This is important because the lru_cache() will hash
-        the key multiple times on a cache miss.
-    """
-
-    __slots__ = 'hashvalue'
-
-    def __init__(self, tup, hash=hash):
-        self[:] = tup
-        self.hashvalue = hash(tup)
-
-    def __hash__(self):
-        return self.hashvalue
-
-def _make_key(args, kwds, typed,
-             kwd_mark = (object(),),
-             fasttypes = set([int, str, frozenset, type(None)]),
-             sorted=sorted, tuple=tuple, type=type, len=len):
-    """Make a cache key from optionally typed positional and keyword arguments
-    The key is constructed in a way that is flat as possible rather than
-    as a nested structure that would take more memory.
-    If there is only a single argument and its data type is known to cache
-    its hash value, then that argument is returned without a wrapper.  This
-    saves space and improves lookup speed.
-    """
-    key = args
-    if kwds:
-        sorted_items = sorted(kwds.items())
-        key += kwd_mark
-        for item in sorted_items:
-            key += item
-    if typed:
-        key += tuple(type(v) for v in args)
-        if kwds:
-            key += tuple(type(v) for k, v in sorted_items)
-    elif len(key) == 1 and type(key[0]) in fasttypes:
-        return key[0]
-    return _HashedSeq(key)
-
-def lru_cache(maxsize=128, typed=False):
-    """Least-recently-used cache decorator.
-    If *maxsize* is set to None, the LRU features are disabled and the cache
-    can grow without bound.
-    If *typed* is True, arguments of different types will be cached separately.
-    For example, f(3.0) and f(3) will be treated as distinct calls with
-    distinct results.
-    Arguments to the cached function must be hashable.
-    View the cache statistics named tuple (hits, misses, maxsize, currsize)
-    with f.cache_info().  Clear the cache and statistics with f.cache_clear().
-    Access the underlying function with f.__wrapped__.
-    See:  http://en.wikipedia.org/wiki/Cache_algorithms#Least_Recently_Used
-    """
-
-    # Users should only access the lru_cache through its public API:
-    #       cache_info, cache_clear, and f.__wrapped__
-    # The internals of the lru_cache are encapsulated for thread safety and
-    # to allow the implementation to change (including a possible C version).
-
-    # Early detection of an erroneous call to @lru_cache without any arguments
-    # resulting in the inner function being passed to maxsize instead of an
-    # integer or None.
-    if maxsize is not None and not isinstance(maxsize, int):
-        raise TypeError('Expected maxsize to be an integer or None')
-
-    def decorating_function(user_function):
-        wrapper = _lru_cache_wrapper(user_function, maxsize, typed)
-        return update_wrapper(wrapper, user_function)
-
-    return decorating_function
-
-def _lru_cache_wrapper(user_function, maxsize, typed):
-    # Constants shared by all lru cache instances:
-    sentinel = object()          # unique object used to signal cache misses
-    make_key = _make_key         # build a key from the function arguments
-    PREV, NEXT, KEY, RESULT = 0, 1, 2, 3   # names for the link fields
-
-    cache = {}
-    cache_get = cache.get    # bound method to lookup a key or return None
-    lock = RLock()           # because linkedlist updates aren't threadsafe
-    root = []                # root of the circular doubly linked list
-    root[:] = [root, root, None, None]     # initialize by pointing to self
-    hits_misses_full_root = [0, 0, False, root]
-    HITS,MISSES,FULL,ROOT = 0, 1, 2, 3
-
-    if maxsize == 0:
-
-        def wrapper(*args, **kwds):
-            # No caching -- just a statistics update after a successful call
-            result = user_function(*args, **kwds)
-            hits_misses_full_root[MISSES] += 1
-            return result
-
-    elif maxsize is None:
-
-        def wrapper(*args, **kwds):
-            # Simple caching without ordering or size limit
-            key = make_key(args, kwds, typed)
-            result = cache_get(key, sentinel)
-            if result is not sentinel:
-                hits_misses_full_root[HITS] += 1
-                return result
-            result = user_function(*args, **kwds)
-            cache[key] = result
-            hits_misses_full_root[MISSES] += 1
-            return result
-
-    else:
-
-        def wrapper(*args, **kwds):
-            # Size limited caching that tracks accesses by recency
-            key = make_key(args, kwds, typed)
-            lock.acquire()
-            try:
-                link = cache_get(key)
-                if link is not None:
-                    # Move the link to the front of the circular queue
-                    root = hits_misses_full_root[ROOT]
-                    link_prev, link_next, _key, result = link
-                    link_prev[NEXT] = link_next
-                    link_next[PREV] = link_prev
-                    last = root[PREV]
-                    last[NEXT] = root[PREV] = link
-                    link[PREV] = last
-                    link[NEXT] = root
-                    hits_misses_full_root[HITS] += 1
-                    return result
-            finally:
-                lock.release()
-            result = user_function(*args, **kwds)
-            lock.acquire()
-            try:
-                if key in cache:
-                    # Getting here means that this same key was added to the
-                    # cache while the lock was released.  Since the link
-                    # update is already done, we need only return the
-                    # computed result and update the count of misses.
-                    pass
-                elif hits_misses_full_root[FULL]:
-                    # Use the old root to store the new key and result.
-                    oldroot = root = hits_misses_full_root[ROOT]
-                    oldroot[KEY] = key
-                    oldroot[RESULT] = result
-                    # Empty the oldest link and make it the new root.
-                    # Keep a reference to the old key and old result to
-                    # prevent their ref counts from going to zero during the
-                    # update. That will prevent potentially arbitrary object
-                    # clean-up code (i.e. __del__) from running while we're
-                    # still adjusting the links.
-                    root = hits_misses_full_root[ROOT] = oldroot[NEXT]
-                    oldkey = root[KEY]
-                    oldresult = root[RESULT]
-                    root[KEY] = root[RESULT] = None
-                    # Now update the cache dictionary.
-                    del cache[oldkey]
-                    # Save the potentially reentrant cache[key] assignment
-                    # for last, after the root and links have been put in
-                    # a consistent state.
-                    cache[key] = oldroot
-                else:
-                    # Put result in a new link at the front of the queue.
-                    root = hits_misses_full_root[ROOT]
-                    last = root[PREV]
-                    link = [last, root, key, result]
-                    last[NEXT] = root[PREV] = cache[key] = link
-                    # Use the __len__() method instead of the len() function
-                    # which could potentially be wrapped in an lru_cache itself.
-                    hits_misses_full_root[FULL] = (cache.__len__() >= maxsize)
-                hits_misses_full_root[MISSES]
-            finally:
-                lock.release()
-            return result
-
-    def cache_clear():
-        """Clear the cache and cache statistics"""
-        lock.acquire()
-        try:
-            cache.clear()
-            root = hits_misses_full_root[ROOT]
-            root[:] = [root, root, None, None]
-            hits_misses_full[HITS] = 0
-            hits_misses_full[MISSES] = 0
-            hits_misses_full[FULL] = False
-        finally:
-            lock.release()
-
-    wrapper.cache_clear = cache_clear
-    return wrapper

mitogen/compat/pkgutil.py

@@ -1,5 +1,7 @@
 """Utilities to support packages."""
 
+# !mitogen: minify_safe
+
 # NOTE: This module must remain compatible with Python 2.3, as it is shared
 # by setuptools for distribution with Python 2.3 and up.
 

mitogen/compat/tokenize.py

@@ -22,6 +22,8 @@ are the same, except instead of generating tokens, tokeneater is a callback
 function to which the 5 fields described above are passed as 5 arguments,
 each time a new token is found."""
 
+# !mitogen: minify_safe
+
 __author__ = 'Ka-Ping Yee <ping@lfw.org>'
 __credits__ = ('GvR, ESR, Tim Peters, Thomas Wouters, Fred Drake, '
                'Skip Montanaro, Raymond Hettinger')

mitogen/core.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 This module implements most package functionality, but remains separate from
 non-essential code in order to reduce its size, since it is also serves as the
@@ -40,8 +42,9 @@ import fcntl
 import itertools
 import linecache
 import logging
-import pickle as py_pickle
 import os
+import pickle as py_pickle
+import pstats
 import signal
 import socket
 import struct
@@ -60,6 +63,11 @@ import imp
 # Absolute imports for <2.5.
 select = __import__('select')
 
+try:
+    import cProfile
+except ImportError:
+    cProfile = None
+
 try:
     import thread
 except ImportError:
@@ -528,21 +536,37 @@ def enable_debug_logging():
 
 
 _profile_hook = lambda name, func, *args: func(*args)
+_profile_fmt = os.environ.get(
+    'MITOGEN_PROFILE_FMT',
+    '/tmp/mitogen.stats.%(pid)s.%(identity)s.%(now)s.%(ext)s',
+)
 
 
-def enable_profiling():
-    global _profile_hook
-    import cProfile
-    import pstats
-    def _profile_hook(name, func, *args):
+def _profile_hook(name, func, *args):
+    """
+    Call `func(*args)` and return its result. This function is replaced by
+    :func:`_real_profile_hook` when :func:`enable_profiling` is called. This
+    interface is obsolete and will be replaced by a signals-based integration
+    later on.
+    """
+    return func(*args)
+
+
+def _real_profile_hook(name, func, *args):
     profiler = cProfile.Profile()
     profiler.enable()
     try:
         return func(*args)
     finally:
-            profiler.dump_stats('/tmp/mitogen.stats.%d.%s.pstat' % (os.getpid(), name))
+        path = _profile_fmt % {
+            'now': int(1e6 * time.time()),
+            'identity': name,
+            'pid': os.getpid(),
+            'ext': '%s'
+        }
+        profiler.dump_stats(path % ('pstats',))
         profiler.create_stats()
-            fp = open('/tmp/mitogen.stats.%d.%s.log' % (os.getpid(), name), 'w')
+        fp = open(path % ('log',), 'w')
         try:
             stats = pstats.Stats(profiler, stream=fp)
             stats.sort_stats('cumulative')
@@ -551,6 +575,11 @@ def enable_profiling():
             fp.close()
 
 
+def enable_profiling(econtext=None):
+    global _profile_hook
+    _profile_hook = _real_profile_hook
+
+
 def import_module(modname):
     """
     Import `module` and return the attribute named `attr`.
@@ -1684,11 +1713,9 @@ class Stream(BasicStream):
                           msg.reply_to or 0, len(msg.data)) + msg.data
 
         if not self._output_buf_len:
-            # Modifying epoll/Kqueue state is expensive, as is needless broker
-            # loop iterations. Rather than wait for writeability, simply
-            # attempt to write immediately, and only fall back to
-            # start_transmit()/on_transmit() if an error occurred or the socket
-            # buffer was full.
+            # Modifying epoll/Kqueue state is expensive, as are needless broker
+            # loops. Rather than wait for writeability, just write immediately,
+            # and fall back to the broker loop on error or full buffer.
             try:
                 n = self.transmit_side.write(pkt)
                 if n:
@@ -1698,7 +1725,6 @@ class Stream(BasicStream):
             except OSError:
                 pass
 
-        if not self._output_buf_len:
             self._router.broker._start_transmit(self)
         self._output_buf.append(pkt)
         self._output_buf_len += len(pkt)
@@ -2816,7 +2842,7 @@ class Broker(object):
         )
         self._thread = threading.Thread(
             target=self._broker_main,
-            name='mitogen-broker'
+            name='mitogen.broker'
         )
         self._thread.start()
 
@@ -2968,7 +2994,7 @@ class Broker(object):
         self._broker_exit()
 
     def _broker_main(self):
-        _profile_hook('mitogen-broker', self._do_broker_main)
+        _profile_hook('mitogen.broker', self._do_broker_main)
         fire(self, 'exit')
 
     def shutdown(self):
@@ -3064,7 +3090,7 @@ class Dispatcher(object):
         if self.econtext.config.get('on_start'):
             self.econtext.config['on_start'](self.econtext)
 
-        _profile_hook('main', self._dispatch_calls)
+        _profile_hook('mitogen.child_main', self._dispatch_calls)
 
 
 class ExternalContext(object):

mitogen/debug.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 Basic signal handler for dumping thread stacks.
 """

mitogen/doas.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 
 import mitogen.core

mitogen/docker.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 
 import mitogen.core

mitogen/fakessh.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 :mod:`mitogen.fakessh` is a stream implementation that starts a subprocess with
 its environment modified such that ``PATH`` searches for `ssh` return a Mitogen

mitogen/fork.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 import os
 import random

mitogen/jail.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 
 import mitogen.core

mitogen/kubectl.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 
 import mitogen.core

mitogen/lxc.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 
 import mitogen.core

mitogen/lxd.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 
 import mitogen.core

mitogen/master.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 This module implements functionality required by master processes, such as
 starting new contexts via SSH. Its size is also restricted, since it must
@@ -140,7 +142,7 @@ def get_child_modules(path):
     return [to_text(name) for _, name, _ in it]
 
 
-def get_core_source():
+def _get_core_source():
     """
     Master version of parent.get_core_source().
     """
@@ -150,7 +152,7 @@ def get_core_source():
 
 if mitogen.is_master:
     # TODO: find a less surprising way of installing this.
-    mitogen.parent.get_core_source = get_core_source
+    mitogen.parent._get_core_source = _get_core_source
 
 
 LOAD_CONST = dis.opname.index('LOAD_CONST')
@@ -707,10 +709,15 @@ class ModuleResponder(object):
         self.blacklist = []
         self.whitelist = ['']
 
+        #: Context -> set([fullname, ..])
+        self._forwarded_by_context = {}
+
         #: Number of GET_MODULE messages received.
         self.get_module_count = 0
         #: Total time spent in uncached GET_MODULE.
         self.get_module_secs = 0.0
+        #: Total time spent minifying modules.
+        self.minify_secs = 0.0
         #: Number of successful LOAD_MODULE messages sent.
         self.good_load_module_count = 0
         #: Total bytes in successful LOAD_MODULE payloads.
@@ -767,6 +774,8 @@ class ModuleResponder(object):
     def _make_negative_response(self, fullname):
         return (fullname, None, None, None, ())
 
+    minify_safe_re = re.compile(b(r'\s+#\s*!mitogen:\s*minify_safe'))
+
     def _build_tuple(self, fullname):
         if fullname in self._cache:
             return self._cache[fullname]
@@ -792,6 +801,12 @@ class ModuleResponder(object):
             self._cache[fullname] = tup
             return tup
 
+        if self.minify_safe_re.search(source):
+            # If the module contains a magic marker, it's safe to minify.
+            t0 = time.time()
+            source = mitogen.minify.minimize_source(source).encode('utf-8')
+            self.minify_secs += time.time() - t0
+
         if is_pkg:
             pkg_present = get_child_modules(path)
             LOG.debug('_build_tuple(%r, %r) -> %r',
@@ -820,13 +835,14 @@ class ModuleResponder(object):
 
     def _send_load_module(self, stream, fullname):
         if fullname not in stream.sent_modules:
-            LOG.debug('_send_load_module(%r, %r)', stream, fullname)
             tup = self._build_tuple(fullname)
             msg = mitogen.core.Message.pickled(
                 tup,
                 dst_id=stream.remote_id,
                 handle=mitogen.core.LOAD_MODULE,
             )
+            LOG.debug('%s: sending module %s (%.2f KiB)',
+                      stream.name, fullname, len(msg.data) / 1024.0)
             self._router._async_route(msg)
             stream.sent_modules.add(fullname)
             if tup[2] is not None:
@@ -846,6 +862,9 @@ class ModuleResponder(object):
         )
 
     def _send_module_and_related(self, stream, fullname):
+        if fullname in stream.sent_modules:
+            return
+
         try:
             tup = self._build_tuple(fullname)
             for name in tup[4]:  # related
@@ -889,6 +908,14 @@ class ModuleResponder(object):
             )
 
     def _forward_one_module(self, context, fullname):
+        forwarded = self._forwarded_by_context.get(context)
+        if forwarded is None:
+            forwarded = set()
+            self._forwarded_by_context[context] = forwarded
+
+        if fullname in forwarded:
+            return
+
         path = []
         while fullname:
             path.append(fullname)
@@ -984,7 +1011,7 @@ class Router(mitogen.parent.Router):
     #: of any :class:`Broker`, e.g. via::
     #:
     #:      mitogen.master.Router.profiling = True
-    profiling = False
+    profiling = os.environ.get('MITOGEN_PROFILING') is not None
 
     def __init__(self, broker=None, max_message_size=None):
         if broker is None:
@@ -1009,6 +1036,7 @@ class Router(mitogen.parent.Router):
         super(Router, self)._on_broker_exit()
         dct = self.get_stats()
         dct['self'] = self
+        dct['minify_ms'] = 1000 * dct['minify_secs']
         dct['get_module_ms'] = 1000 * dct['get_module_secs']
         dct['good_load_module_size_kb'] = dct['good_load_module_size'] / 1024.0
         dct['good_load_module_size_avg'] = (
@@ -1022,7 +1050,8 @@ class Router(mitogen.parent.Router):
             '%(self)r: stats: '
                 '%(get_module_count)d module requests in '
                 '%(get_module_ms)d ms, '
-                '%(good_load_module_count)d sent, '
+                '%(good_load_module_count)d sent '
+                '(%(minify_ms)d ms minify time), '
                 '%(bad_load_module_count)d negative responses. '
                 'Sent %(good_load_module_size_kb).01f kb total, '
                 '%(good_load_module_size_avg).01f kb avg.'
@@ -1047,6 +1076,8 @@ class Router(mitogen.parent.Router):
               :data:`mitogen.core.LOAD_MODULE` message payloads.
             * `bad_load_module_count`: Integer count of negative
               :data:`mitogen.core.LOAD_MODULE` messages sent.
+            * `minify_secs`: CPU seconds spent minifying modules marked
+               minify-safe.
         """
         return {
             'get_module_count': self.responder.get_module_count,
@@ -1054,6 +1085,7 @@ class Router(mitogen.parent.Router):
             'good_load_module_count': self.responder.good_load_module_count,
             'good_load_module_size': self.responder.good_load_module_size,
             'bad_load_module_count': self.responder.bad_load_module_count,
+            'minify_secs': self.responder.minify_secs,
         }
 
     def enable_debug(self):

mitogen/minify.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import sys
 
 try:
@@ -40,13 +42,7 @@ if sys.version_info < (2, 7, 11):
 else:
     import tokenize
 
-try:
-    from functools import lru_cache
-except ImportError:
-    from mitogen.compat.functools import lru_cache
-
 
-@lru_cache()
 def minimize_source(source):
     """Remove comments and docstrings from Python `source`, preserving line
     numbers and syntax of empty blocks.

mitogen/parent.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 This module defines functionality common to master and parent processes. It is
 sent to any child context that is due to become a parent, due to recursive
@@ -115,6 +117,11 @@ def _ioctl_cast(n):
     return n
 
 
+# If not :data:`None`, called prior to exec() of any new child process. Used by
+# :func:`mitogen.utils.reset_affinity` to allow the child to be freely
+# scheduled.
+_preexec_hook = None
+
 # Get PTY number; asm-generic/ioctls.h
 LINUX_TIOCGPTN = _ioctl_cast(2147767344)
 
@@ -150,7 +157,11 @@ def get_sys_executable():
     return '/usr/bin/python'
 
 
-def get_core_source():
+_core_source_lock = threading.Lock()
+_core_source_partial = None
+
+
+def _get_core_source():
     """
     In non-masters, simply fetch the cached mitogen.core source code via the
     import mechanism. In masters, this function is replaced with a version that
@@ -159,6 +170,26 @@ def get_core_source():
     return inspect.getsource(mitogen.core)
 
 
+def get_core_source_partial():
+    """
+    _get_core_source() is expensive, even with @lru_cache in minify.py, threads
+    can enter it simultaneously causing severe slowdowns.
+    """
+    global _core_source_partial
+
+    if _core_source_partial is None:
+        _core_source_lock.acquire()
+        try:
+            if _core_source_partial is None:
+                _core_source_partial = PartialZlib(
+                    _get_core_source().encode('utf-8')
+                )
+        finally:
+            _core_source_lock.release()
+
+    return _core_source_partial
+
+
 def get_default_remote_name():
     """
     Return the default name appearing in argv[0] of remote machines.
@@ -262,7 +293,13 @@ def detach_popen(**kwargs):
     # handling, without tying the surrounding code into managing a Popen
     # object, which isn't possible for at least :mod:`mitogen.fork`. This
     # should be replaced by a swappable helper class in a future version.
-    proc = subprocess.Popen(**kwargs)
+    real_preexec_fn = kwargs.pop('preexec_fn', None)
+    def preexec_fn():
+        if _preexec_hook:
+            _preexec_hook()
+        if real_preexec_fn:
+            real_preexec_fn()
+    proc = subprocess.Popen(preexec_fn=preexec_fn, **kwargs)
     proc._child_created = False
     return proc.pid
 
@@ -419,11 +456,11 @@ def tty_create_child(args):
         `(pid, tty_fd, None)`
     """
     master_fd, slave_fd = openpty()
+    try:
         mitogen.core.set_block(slave_fd)
         disable_echo(master_fd)
         disable_echo(slave_fd)
 
-    try:
         pid = detach_popen(
             args=args,
             stdin=slave_fd,
@@ -456,14 +493,15 @@ def hybrid_tty_create_child(args):
         `(pid, socketpair_fd, tty_fd)`
     """
     master_fd, slave_fd = openpty()
-    parentfp, childfp = create_socketpair()
 
-    mitogen.core.set_block(slave_fd)
-    mitogen.core.set_block(childfp)
+    try:
         disable_echo(master_fd)
         disable_echo(slave_fd)
+        mitogen.core.set_block(slave_fd)
 
+        parentfp, childfp = create_socketpair()
         try:
+            mitogen.core.set_block(childfp)
             pid = detach_popen(
                 args=args,
                 stdin=childfp,
@@ -473,11 +511,13 @@ def hybrid_tty_create_child(args):
                 close_fds=True,
             )
         except Exception:
-        os.close(master_fd)
-        os.close(slave_fd)
             parentfp.close()
             childfp.close()
             raise
+    except Exception:
+        os.close(master_fd)
+        os.close(slave_fd)
+        raise
 
     os.close(slave_fd)
     childfp.close()
@@ -536,6 +576,43 @@ def write_all(fd, s, deadline=None):
         poller.close()
 
 
+class PartialZlib(object):
+    """
+    Because the mitogen.core source has a line appended to it during bootstrap,
+    it must be recompressed for each connection. This is not a problem for a
+    small number of connections, but it amounts to 30 seconds CPU time by the
+    time 500 targets are in use.
+
+    For that reason, build a compressor containing mitogen.core and flush as
+    much of it as possible into an initial buffer. Then to append the custom
+    line, clone the compressor and compress just that line.
+
+    A full compression costs ~6ms on a modern machine, this method costs ~35
+    usec.
+    """
+    def __init__(self, s):
+        self.s = s
+        if sys.version_info > (2, 5):
+            self._compressor = zlib.compressobj(9)
+            self._out = self._compressor.compress(s)
+            self._out += self._compressor.flush(zlib.Z_SYNC_FLUSH)
+        else:
+            self._compressor = None
+
+    def append(self, s):
+        """
+        Append the bytestring `s` to the compressor state and return the
+        final compressed output.
+        """
+        if self._compressor is None:
+            return zlib.compress(self.s + s, 9)
+        else:
+            compressor = self._compressor.copy()
+            out = self._out
+            out += compressor.compress(s)
+            return out + compressor.flush()
+
+
 class IteratingRead(object):
     def __init__(self, fds, deadline=None):
         self.deadline = deadline
@@ -1147,6 +1224,7 @@ class Stream(mitogen.core.Stream):
             LOG.debug('%r: PID %d %s', self, pid, wstatus_to_str(status))
             return
 
+        if not self._router.profiling:
             # For processes like sudo we cannot actually send sudo a signal,
             # because it is setuid, so this is best-effort only.
             LOG.debug('%r: child process still alive, sending SIGTERM', self)
@@ -1263,11 +1341,12 @@ class Stream(mitogen.core.Stream):
         }
 
     def get_preamble(self):
-        source = get_core_source()
-        source += '\nExternalContext(%r).main()\n' % (
-            self.get_econtext_config(),
+        suffix = (
+            '\nExternalContext(%r).main()\n' %\
+            (self.get_econtext_config(),)
         )
-        return zlib.compress(source.encode('utf-8'), 9)
+        partial = get_core_source_partial()
+        return partial.append(suffix.encode('utf-8'))
 
     def start_child(self):
         args = self.get_boot_command()

mitogen/profiler.py

@@ -0,0 +1,166 @@
+# Copyright 2017, David Wilson
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# 1. Redistributions of source code must retain the above copyright notice,
+# this list of conditions and the following disclaimer.
+#
+# 2. Redistributions in binary form must reproduce the above copyright notice,
+# this list of conditions and the following disclaimer in the documentation
+# and/or other materials provided with the distribution.
+#
+# 3. Neither the name of the copyright holder nor the names of its contributors
+# may be used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+# !mitogen: minify_safe
+
+"""mitogen.profiler
+    Record and report cProfile statistics from a run. Creates one aggregated
+    output file, one aggregate containing only workers, and one for the
+    top-level process.
+
+Usage:
+    mitogen.profiler record <dest_path> <tool> [args ..]
+    mitogen.profiler report <dest_path> [sort_mode]
+    mitogen.profiler stat <sort_mode> <tool> [args ..]
+
+Mode:
+    record: Record a trace.
+    report: Report on a previously recorded trace.
+    stat: Record and report in a single step.
+
+Where:
+    dest_path: Filesystem prefix to write .pstats files to.
+    sort_mode: Sorting mode; defaults to "cumulative". See:
+        https://docs.python.org/2/library/profile.html#pstats.Stats.sort_stats
+
+Example:
+    mitogen.profiler record /tmp/mypatch ansible-playbook foo.yml
+    mitogen.profiler dump /tmp/mypatch-worker.pstats
+"""
+
+from __future__ import print_function
+import os
+import pstats
+import cProfile
+import shutil
+import subprocess
+import sys
+import tempfile
+import time
+
+import mitogen.core
+
+
+def try_merge(stats, path):
+    try:
+        stats.add(path)
+        return True
+    except Exception as e:
+        print('Failed. Race? Will retry. %s' % (e,))
+        return False
+
+
+def merge_stats(outpath, inpaths):
+    first, rest = inpaths[0], inpaths[1:]
+    for x in range(5):
+        try:
+            stats = pstats.Stats(first)
+        except EOFError:
+            time.sleep(0.2)
+            continue
+
+        print("Writing %r..." % (outpath,))
+        for path in rest:
+            #print("Merging %r into %r.." % (os.path.basename(path), outpath))
+            for x in range(5):
+                if try_merge(stats, path):
+                    break
+                time.sleep(0.2)
+
+    stats.dump_stats(outpath)
+
+
+def generate_stats(outpath, tmpdir):
+    print('Generating stats..')
+    all_paths = []
+    paths_by_ident = {}
+
+    for name in os.listdir(tmpdir):
+        if name.endswith('-dump.pstats'):
+            ident, _, pid = name.partition('-')
+            path = os.path.join(tmpdir, name)
+            all_paths.append(path)
+            paths_by_ident.setdefault(ident, []).append(path)
+
+    merge_stats('%s-all.pstat' % (outpath,), all_paths)
+    for ident, paths in paths_by_ident.items():
+        merge_stats('%s-%s.pstat' % (outpath, ident), paths)
+
+
+def do_record(tmpdir, path, *args):
+    env = os.environ.copy()
+    fmt = '%(identity)s-%(pid)s.%(now)s-dump.%(ext)s'
+    env['MITOGEN_PROFILING'] = '1'
+    env['MITOGEN_PROFILE_FMT'] = os.path.join(tmpdir, fmt)
+    rc = subprocess.call(args, env=env)
+    generate_stats(path, tmpdir)
+    return rc
+
+
+def do_report(tmpdir, path, sort='cumulative'):
+    stats = pstats.Stats(path).sort_stats(sort)
+    stats.print_stats(100)
+
+
+def do_stat(tmpdir, sort, *args):
+    valid_sorts = pstats.Stats.sort_arg_dict_default
+    if sort not in valid_sorts:
+        sys.stderr.write('Invalid sort %r, must be one of %s\n' %
+                         (sort, ', '.join(sorted(valid_sorts))))
+        sys.exit(1)
+
+    outfile = os.path.join(tmpdir, 'combined')
+    do_record(tmpdir, outfile, *args)
+    aggs = ('app.main', 'mitogen.broker', 'mitogen.child_main',
+            'mitogen.service.pool', 'Strategy', 'WorkerProcess',
+            'all')
+    for agg in aggs:
+        path = '%s-%s.pstat' % (outfile, agg)
+        if os.path.exists(path):
+            print()
+            print()
+            print('------ Aggregation %r ------' % (agg,))
+            print()
+            do_report(tmpdir, path, sort)
+            print()
+
+
+def main():
+    if len(sys.argv) < 2 or sys.argv[1] not in ('record', 'report', 'stat'):
+        sys.stderr.write(__doc__)
+        sys.exit(1)
+
+    func = globals()['do_' + sys.argv[1]]
+    tmpdir = tempfile.mkdtemp(prefix='mitogen.profiler')
+    try:
+        sys.exit(func(tmpdir, *sys.argv[2:]) or 0)
+    finally:
+        shutil.rmtree(tmpdir)
+
+if __name__ == '__main__':
+    main()

mitogen/select.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import mitogen.core
 
 

mitogen/service.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import grp
 import os
 import os.path
@@ -80,6 +82,10 @@ def get_or_create_pool(size=None, router=None):
         if _pool_pid != os.getpid():
             _pool = Pool(router, [], size=size or DEFAULT_POOL_SIZE,
                          overwrite=True)
+            # In case of Broker shutdown crash, Pool can cause 'zombie'
+            # processes.
+            mitogen.core.listen(router.broker, 'shutdown',
+                                lambda: _pool.stop(join=False))
             _pool_pid = os.getpid()
         return _pool
     finally:
@@ -467,7 +473,7 @@ class Pool(object):
             thread = threading.Thread(
                 name=name,
                 target=mitogen.core._profile_hook,
-                args=(name, self._worker_main),
+                args=('mitogen.service.pool', self._worker_main),
             )
             thread.start()
             self._threads.append(thread)
@@ -634,7 +640,7 @@ class PushFileService(Service):
                 path=path,
                 context=context
             ).close()
-        else:
+        elif path not in sent:
             child.call_service_async(
                 service_name=self.name(),
                 method_name='store_and_forward',
@@ -642,6 +648,7 @@ class PushFileService(Service):
                 data=self._cache[path],
                 context=context
             ).close()
+            sent.add(path)
 
     @expose(policy=AllowParents())
     @arg_spec({
@@ -708,7 +715,7 @@ class PushFileService(Service):
         if path not in self._cache:
             LOG.error('%r: %r is not in local cache', self, path)
             return
-        self._forward(path, context)
+        self._forward(context, path)
 
 
 class FileService(Service):

mitogen/setns.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import ctypes
 import grp
 import logging

mitogen/ssh.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 Functionality to allow establishing new slave contexts over an SSH connection.
 """

mitogen/su.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import logging
 
 import mitogen.core
@@ -64,6 +66,7 @@ class Stream(mitogen.parent.Stream):
         b('su: sorry'),                    # BSD
         b('su: authentication failure'),   # Linux
         b('su: incorrect password'),       # CentOS 6
+        b('authentication is denied'),     # AIX
     )
 
     def construct(self, username=None, password=None, su_path=None,

mitogen/sudo.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import base64
 import logging
 import optparse

mitogen/unix.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 """
 Permit connection of additional contexts that may act with the authority of
 this context. For now, the UNIX socket is always mode 0600, i.e. can only be

mitogen/utils.py

@@ -26,6 +26,8 @@
 # ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 # POSSIBILITY OF SUCH DAMAGE.
 
+# !mitogen: minify_safe
+
 import datetime
 import logging
 import os
@@ -34,6 +36,7 @@ import sys
 import mitogen
 import mitogen.core
 import mitogen.master
+import mitogen.parent
 
 
 LOG = logging.getLogger('mitogen')

tests/ansible/ansible.cfg

@@ -28,5 +28,5 @@ timeout = 10
 host_key_checking = False
 
 [ssh_connection]
-ssh_args = -o ForwardAgent=yes -o ControlMaster=auto -o ControlPersist=60s
+ssh_args = -o UserKnownHostsFile=/dev/null -o ForwardAgent=yes -o ControlMaster=auto -o ControlPersist=60s
 pipelining = True

tests/ansible/bench/loop-100-items.yml

@@ -7,4 +7,4 @@
 - hosts: all
   tasks:
     - command: hostname
-      with_sequence: start=1 end=100
+      with_sequence: start=1 end="{{end|default(100)}}"

tests/ansible/bench/loop-20-templates.yml

@@ -11,4 +11,4 @@
       mode: 0755
       content:
         Hello from {{item}}
-    with_sequence: start=1 end=20
+    with_sequence: start=1 end={{end|default(20)}}

tests/ansible/hosts/localhost.hosts

@@ -7,4 +7,31 @@ localhost
 
 # This is only used for manual testing.
 [localhost-x10]
-localhost-[01:10]
+localhost-[001:010]
+
+[localhost-x20]
+localhost-[001:020]
+
+[localhost-x30]
+localhost-[001:030]
+
+[localhost-x40]
+localhost-[001:040]
+
+[localhost-x50]
+localhost-[001:050]
+
+[localhost-x60]
+localhost-[001:060]
+
+[localhost-x70]
+localhost-[001:070]
+
+[localhost-x80]
+localhost-[001:080]
+
+[localhost-x90]
+localhost-[001:090]
+
+[localhost-x100]
+localhost-[001:100]

tests/ansible/integration/connection_delegation/delegate_to_template.yml

@@ -32,6 +32,7 @@
           {
             'kwargs': {
               'check_host_keys': 'ignore',
+              'compression': True,
               'connect_timeout': 10,
               'hostname': 'alias-host',
               'identities_only': False,
@@ -40,6 +41,8 @@
               'port': null,
               'python_path': null,
               'ssh_args': [
+                '-o',
+                'UserKnownHostsFile=/dev/null',
                 '-o',
                 'ForwardAgent=yes',
                 '-o',
@@ -56,6 +59,7 @@
           {
             'kwargs': {
               'check_host_keys': 'ignore',
+              'compression': True,
               'connect_timeout': 10,
               'hostname': 'cd-normal-alias',
               'identities_only': False,
@@ -64,6 +68,8 @@
               'port': null,
               'python_path': null,
               'ssh_args': [
+                '-o',
+                'UserKnownHostsFile=/dev/null',
                 '-o',
                 'ForwardAgent=yes',
                 '-o',

tests/ansible/integration/connection_delegation/stack_construction.yml

@@ -65,6 +65,7 @@
               {
                   'kwargs': {
                       'check_host_keys': 'ignore',
+                      'compression': True,
                       'connect_timeout': 10,
                       'hostname': 'alias-host',
                       'identities_only': False,
@@ -73,6 +74,8 @@
                       'port': null,
                       'python_path': null,
                       'ssh_args': [
+                          '-o',
+                          'UserKnownHostsFile=/dev/null',
                           '-o',
                           'ForwardAgent=yes',
                           '-o',
@@ -102,6 +105,7 @@
               {
                   'kwargs': {
                       'check_host_keys': 'ignore',
+                      'compression': True,
                       'connect_timeout': 10,
                       'hostname': 'alias-host',
                       'identities_only': False,
@@ -110,6 +114,8 @@
                       'port': null,
                       'python_path': null,
                       'ssh_args': [
+                          '-o',
+                          'UserKnownHostsFile=/dev/null',
                           '-o',
                           'ForwardAgent=yes',
                           '-o',
@@ -149,6 +155,7 @@
               {
                   'kwargs': {
                       'check_host_keys': 'ignore',
+                      'compression': True,
                       'connect_timeout': 10,
                       'hostname': 'cd-normal-normal',
                       'identities_only': False,
@@ -157,6 +164,8 @@
                       'port': null,
                       'python_path': null,
                       'ssh_args': [
+                          '-o',
+                          'UserKnownHostsFile=/dev/null',
                           '-o',
                           'ForwardAgent=yes',
                           '-o',
@@ -186,6 +195,7 @@
               {
                   'kwargs': {
                       'check_host_keys': 'ignore',
+                      'compression': True,
                       'connect_timeout': 10,
                       'hostname': 'alias-host',
                       'identities_only': False,
@@ -194,6 +204,8 @@
                       'port': null,
                       'python_path': null,
                       'ssh_args': [
+                          '-o',
+                          'UserKnownHostsFile=/dev/null',
                           '-o',
                           'ForwardAgent=yes',
                           '-o',
@@ -210,6 +222,7 @@
               {
                   'kwargs': {
                       'check_host_keys': 'ignore',
+                      'compression': True,
                       'connect_timeout': 10,
                       'hostname': 'cd-normal-alias',
                       'identities_only': False,
@@ -218,6 +231,8 @@
                       'port': null,
                       'python_path': null,
                       'ssh_args': [
+                          '-o',
+                          'UserKnownHostsFile=/dev/null',
                           '-o',
                           'ForwardAgent=yes',
                           '-o',
@@ -257,6 +272,7 @@
               {
                   'kwargs': {
                       'check_host_keys': 'ignore',
+                      'compression': True,
                       'connect_timeout': 10,
                       'hostname': 'cd-newuser-normal-normal',
                       'identities_only': False,
@@ -265,6 +281,8 @@
                       'port': null,
                       'python_path': null,
                       'ssh_args': [
+                          '-o',
+                          'UserKnownHostsFile=/dev/null',
                           '-o',
                           'ForwardAgent=yes',
                           '-o',
@@ -295,6 +313,7 @@
               {
                   'kwargs': {
                       'check_host_keys': 'ignore',
+                      'compression': True,
                       'connect_timeout': 10,
                       'hostname': 'alias-host',
                       'identities_only': False,
@@ -303,6 +322,8 @@
                       'port': null,
                       'python_path': null,
                       'ssh_args': [
+                          '-o',
+                          'UserKnownHostsFile=/dev/null',
                           '-o',
                           'ForwardAgent=yes',
                           '-o',

tests/ansible/lib/action/mitogen_shutdown_all.py

@@ -12,6 +12,9 @@ from ansible.plugins.action import ActionBase
 
 
 class ActionModule(ActionBase):
+    # Running this for every host is pointless.
+    BYPASS_HOST_LOOP = True
+
     def run(self, tmp=None, task_vars=None):
         if not isinstance(self._connection,
                           ansible_mitogen.connection.Connection):

tests/ansible/tests/affinity_test.py

@@ -0,0 +1,63 @@
+
+import multiprocessing
+import os
+import tempfile
+
+import mock
+import unittest2
+import testlib
+
+import mitogen.parent
+import ansible_mitogen.affinity
+
+
+@unittest2.skipIf(
+    reason='Linux/SMP only',
+    condition=(not (
+        os.uname()[0] == 'Linux' and
+        multiprocessing.cpu_count() >= 4
+    ))
+)
+class LinuxPolicyTest(testlib.TestCase):
+    klass = ansible_mitogen.affinity.LinuxPolicy
+
+    def setUp(self):
+        self.policy = self.klass()
+
+    def _get_cpus(self, path='/proc/self/status'):
+        fp = open(path)
+        try:
+            for line in fp:
+                if line.startswith('Cpus_allowed'):
+                    return int(line.split()[1], 16)
+        finally:
+            fp.close()
+
+    def test_set_clear(self):
+        before = self._get_cpus()
+        self.policy._set_cpu(3)
+        self.assertEquals(self._get_cpus(), 1 << 3)
+        self.policy._clear()
+        self.assertEquals(self._get_cpus(), before)
+
+    def test_clear_on_popen(self):
+        tf = tempfile.NamedTemporaryFile()
+        try:
+            before = self._get_cpus()
+            self.policy._set_cpu(3)
+            my_cpu = self._get_cpus()
+
+            pid = mitogen.parent.detach_popen(
+                args=['cp', '/proc/self/status', tf.name]
+            )
+            os.waitpid(pid, 0)
+
+            his_cpu = self._get_cpus(tf.name)
+            self.assertNotEquals(my_cpu, his_cpu)
+            self.policy._clear()
+        finally:
+            tf.close()
+
+
+if __name__ == '__main__':
+    unittest2.main()

tests/bench/latch_roundtrip.py

@@ -7,8 +7,10 @@ import time
 
 import mitogen
 import mitogen.utils
+import ansible_mitogen.affinity
 
 mitogen.utils.setup_gil()
+ansible_mitogen.affinity.policy.assign_worker()
 
 X = 20000
 

tests/bench/linux_record_cpu_net.sh

@@ -6,7 +6,19 @@
 #
 
 [ ! "$1" ] && exit 1
-sudo tcpdump -w $1-out.cap -s 0 host k1.botanicus.net &
-date +%s.%N > $1-task-clock.csv
-perf stat -x, -I 25 -e task-clock --append -o $1-task-clock.csv ansible-playbook run_hostname_100_times.yml
+name="$1"; shift
+
+
+sudo tcpdump -i any -w $name-net.pcap -s 66 port 22 or port 9122 &
+sleep 0.5
+
+perf stat -x, -I 100 \
+    -e branches \
+    -e instructions \
+    -e task-clock \
+    -e context-switches \
+    -e page-faults \
+    -e cpu-migrations \
+    -o $name-perf.csv "$@"
+pkill -f ssh:; sleep 0.1
 sudo pkill -f tcpdump

tests/bench/local.py

@@ -2,19 +2,23 @@
 Measure latency of .local() setup.
 """
 
-import mitogen
 import time
 
+import mitogen
+import mitogen.utils
+import ansible_mitogen.affinity
+
+
+mitogen.utils.setup_gil()
+#ansible_mitogen.affinity.policy.assign_worker()
+
 
 @mitogen.main()
 def main(router):
-    for x in range(1000):
+    t0=time.time()
+    for x in range(100):
         t = time.time()
         f = router.local()# debug=True)
         tt = time.time()
         print(x, 1000 * (tt - t))
-
-    print(f)
-    print('EEK', f.call(socket.gethostname))
-    print('MY PID', os.getpid())
-    print('EEKERY', f.call(os.getpid))
+    print('%.03f ms' % (1000 * (time.time() - t0) / (1.0 + x)))

tests/bench/roundtrip.py

@@ -6,8 +6,10 @@ import time
 
 import mitogen
 import mitogen.utils
+import ansible_mitogen.affinity
 
 mitogen.utils.setup_gil()
+ansible_mitogen.affinity.policy.assign_worker()
 
 try:
     xrange

tests/minify_test.py

@@ -1,6 +1,7 @@
 import codecs
 import glob
 import pprint
+import sys
 
 import unittest2
 
@@ -92,8 +93,15 @@ class MitogenCoreTest(testlib.TestCase):
                 'mwords': mwords,
             })
 
+    PY_24_25_SKIP = [
+        # cProfile unsupported on 2.4, 2.6+ syntax is fine here.
+        'mitogen/profiler.py',
+    ]
+
     def test_minify_all(self):
         for name in glob.glob('mitogen/*.py'):
+            if name in self.PY_24_25_SKIP and sys.version_info < (2, 6):
+                continue
             original = self.read_source(name)
             try:
                 minified = self.func(original)

tests/module_finder_test.py

@@ -220,12 +220,11 @@ class FindRelatedTest(testlib.TestCase):
         u'mitogen.parent',
     ])
 
-    if sys.version_info < (3, 2):
-        SIMPLE_EXPECT.add('mitogen.compat')
-        SIMPLE_EXPECT.add('mitogen.compat.functools')
     if sys.version_info < (2, 7):
+        SIMPLE_EXPECT.add('mitogen.compat')
         SIMPLE_EXPECT.add('mitogen.compat.tokenize')
     if sys.version_info < (2, 6):
+        SIMPLE_EXPECT.add('mitogen.compat')
         SIMPLE_EXPECT.add('mitogen.compat.pkgutil')
 
     def test_simple(self):

tests/responder_test.py

@@ -175,7 +175,8 @@ class ForwardTest(testlib.RouterMixin, testlib.TestCase):
         self.assertEquals(256, c2.call(plain_old_module.pow, 2, 8))
         self.assertEquals(2, self.router.responder.get_module_count)
         self.assertEquals(2, self.router.responder.good_load_module_count)
-        self.assertLess(20000, self.router.responder.good_load_module_size)
+        self.assertLess(10000, self.router.responder.good_load_module_size)
+        self.assertGreater(40000, self.router.responder.good_load_module_size)
 
 
 class BlacklistTest(testlib.TestCase):

tests/utils_test.py

@@ -1,8 +1,13 @@
 #!/usr/bin/env python
 
+import os
+import tempfile
+
 import unittest2
+import mock
 
 import mitogen.core
+import mitogen.parent
 import mitogen.master
 import mitogen.utils
 from mitogen.core import b