issue #477: promote setup_gil() to mitogen.utils

This is since ansible_mitogen/process.py is 2.6-only, and I want to use
setup_gil() in 2.4 code.

ansible_mitogen/process.py

@@ -93,27 +93,6 @@ def getenv_int(key, default=0):
         return default
 
 
-def setup_gil():
-    """
-    Set extremely long GIL release interval to let threads naturally progress
-    through CPU-heavy sequences without forcing the wake of another thread that
-    may contend trying to run the same CPU-heavy code. For the new-style work,
-    this drops runtime ~33% and involuntary context switches by >80%,
-    essentially making threads cooperatively scheduled.
-    """
-    try:
-        # Python 2.
-        sys.setcheckinterval(100000)
-    except AttributeError:
-        pass
-
-    try:
-        # Python 3.
-        sys.setswitchinterval(10)
-    except AttributeError:
-        pass
-
-
 class MuxProcess(object):
     """
     Implement a subprocess forked from the Ansible top-level, as a safe place
@@ -177,7 +156,7 @@ class MuxProcess(object):
         if faulthandler is not None:
             faulthandler.enable()
 
-        setup_gil()
+        mitogen.utils.setup_gil()
         cls.unix_listener_path = mitogen.unix.make_socket_path()
         cls.worker_sock, cls.child_sock = socket.socketpair()
         atexit.register(lambda: clean_shutdown(cls.worker_sock))

docs/api.rst

@@ -617,6 +617,7 @@ A random assortment of utility functions useful on masters and children.
 
 
 .. currentmodule:: mitogen.utils
+.. autofunction:: setup_gil
 .. autofunction:: disable_site_packages
 .. autofunction:: log_to_file
 .. autofunction:: run_with_router(func, \*args, \**kwargs)

mitogen/utils.py

@@ -45,6 +45,27 @@ else:
     iteritems = dict.iteritems
 
 
+def setup_gil():
+    """
+    Set extremely long GIL release interval to let threads naturally progress
+    through CPU-heavy sequences without forcing the wake of another thread that
+    may contend trying to run the same CPU-heavy code. For the new-style
+    Ansible work, this drops runtime ~33% and involuntary context switches by
+    >80%, essentially making threads cooperatively scheduled.
+    """
+    try:
+        # Python 2.
+        sys.setcheckinterval(100000)
+    except AttributeError:
+        pass
+
+    try:
+        # Python 3.
+        sys.setswitchinterval(10)
+    except AttributeError:
+        pass
+
+
 def disable_site_packages():
     """
     Remove all entries mentioning ``site-packages`` or ``Extras`` from

tests/bench/latch_roundtrip.py

@@ -6,9 +6,9 @@ import threading
 import time
 
 import mitogen
+import mitogen.utils
 
-import ansible_mitogen.process
-ansible_mitogen.process.setup_gil()
+mitogen.utils.setup_gil()
 
 X = 20000
 

tests/bench/roundtrip.py

@@ -2,11 +2,12 @@
 Measure latency of local RPC.
 """
 
-import mitogen
 import time
 
-import ansible_mitogen.process
-ansible_mitogen.process.setup_gil()
+import mitogen
+import mitogen.utils
+
+mitogen.utils.setup_gil()
 
 try:
     xrange