Commit Graph

3 Commits (dadf15036aba56cbe9cbf2c4f831799a07972ffd)

Author SHA1 Message Date
Will Norris 3ec5be3f51 all: remove AUTHORS file and references to it
This file was never truly necessary and has never actually been used in
the history of Tailscale's open source releases.

A Brief History of AUTHORS files
---

The AUTHORS file was a pattern developed at Google, originally for
Chromium, then adopted by Go and a bunch of other projects. The problem
was that Chromium originally had a copyright line only recognizing
Google as the copyright holder. Because Google (and most open source
projects) do not require copyright assignemnt for contributions, each
contributor maintains their copyright. Some large corporate contributors
then tried to add their own name to the copyright line in the LICENSE
file or in file headers. This quickly becomes unwieldy, and puts a
tremendous burden on anyone building on top of Chromium, since the
license requires that they keep all copyright lines intact.

The compromise was to create an AUTHORS file that would list all of the
copyright holders. The LICENSE file and source file headers would then
include that list by reference, listing the copyright holder as "The
Chromium Authors".

This also become cumbersome to simply keep the file up to date with a
high rate of new contributors. Plus it's not always obvious who the
copyright holder is. Sometimes it is the individual making the
contribution, but many times it may be their employer. There is no way
for the proejct maintainer to know.

Eventually, Google changed their policy to no longer recommend trying to
keep the AUTHORS file up to date proactively, and instead to only add to
it when requested: https://opensource.google/docs/releasing/authors.
They are also clear that:

> Adding contributors to the AUTHORS file is entirely within the
> project's discretion and has no implications for copyright ownership.

It was primarily added to appease a small number of large contributors
that insisted that they be recognized as copyright holders (which was
entirely their right to do). But it's not truly necessary, and not even
the most accurate way of identifying contributors and/or copyright
holders.

In practice, we've never added anyone to our AUTHORS file. It only lists
Tailscale, so it's not really serving any purpose. It also causes
confusion because Tailscalars put the "Tailscale Inc & AUTHORS" header
in other open source repos which don't actually have an AUTHORS file, so
it's ambiguous what that means.

Instead, we just acknowledge that the contributors to Tailscale (whoever
they are) are copyright holders for their individual contributions. We
also have the benefit of using the DCO (developercertificate.org) which
provides some additional certification of their right to make the
contribution.

The source file changes were purely mechanical with:

    git ls-files | xargs sed -i -e 's/\(Tailscale Inc &\) AUTHORS/\1 contributors/g'

Updates #cleanup

Change-Id: Ia101a4a3005adb9118051b3416f5a64a4a45987d
Signed-off-by: Will Norris <will@tailscale.com>
1 week ago
Brad Fitzpatrick 99b06eac49 syncs: add Mutex/RWMutex alias/wrappers for future mutex debugging
Updates #17852

Change-Id: I477340fb8e40686870e981ade11cd61597c34a20
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
3 months ago
James Tucker e8f1721147 syncs: add ShardedInt expvar.Var type
ShardedInt provides an int type expvar.Var that supports more efficient
writes at high frequencies (one order of magnigude on an M1 Max, much
more on NUMA systems).

There are two implementations of ShardValue, one that abuses sync.Pool
that will work on current public Go versions, and one that takes a
dependency on a runtime.TailscaleP function exposed in Tailscale's Go
fork. The sync.Pool variant has about 10x the throughput of a single
atomic integer on an M1 Max, and the runtime.TailscaleP variant is about
10x faster than the sync.Pool variant.

Neither variant have perfect distribution, or perfectly always avoid
cross-CPU sharing, as there is no locking or affinity to ensure that the
time of yield is on the same core as the time of core biasing, but in
the average case the distributions are enough to provide substantially
better performance.

See golang/go#18802 for a related upstream proposal.

Updates tailscale/go#109
Updates tailscale/corp#25450

Signed-off-by: James Tucker <james@tailscale.com>
1 year ago