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>
The encoding/json/v2 effort may end up changing
the default represention of time.Duration in JSON.
See https://go.dev/issue/71631
The GoDuration type allows us to explicitly use
the time.Duration.String representation regardless of
whether we serialize with v1 or v2 of encoding/json.
Updates tailscale/corp#27502
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
Run `staticcheck` with `U1000` to find unused code. This cleans up about
a half of it. I'll do the other half separately to keep PRs manageable.
Updates #cleanup
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
In almost every single use of Clock, there is a default behavior
we want to use when the interface is nil,
which is to use the the standard time package.
The Clock interface exists only for testing,
and so tests that care about mocking time
can adequately plumb the the Clock down the stack
and through various data structures.
However, the problem with Clock is that there are many
situations where we really don't care about mocking time
(e.g., measuring execution time for a log message),
where making sure that Clock is non-nil is not worth the burden.
In fact, in a recent refactoring, the biggest pain point was
dealing with nil-interface panics when calling tstime.Clock methods
where mocking time wasn't even needed for the relevant tests.
This required wasted time carefully reviewing the code to
make sure that tstime.Clock was always populated,
and even then we're not statically guaranteed to avoid a nil panic.
Ideally, what we want are default methods on Go interfaces,
but such a language construct does not exist.
However, we can emulate that behavior by declaring
a concrete type that embeds the interface.
If the underlying interface value is nil,
it provides some default behavior (i.e., use StdClock).
This provides us a nice balance of two goals:
* We can plumb tstime.DefaultClock in all relevant places
for use with mocking time in the tests that care.
* For all other logic that don't care about,
we never need to worry about whether tstime.DefaultClock
is nil or not. This is especially relevant in production code
where we don't want to panic.
Longer-term, we may want to perform a large-scale change
where we rename Clock to ClockInterface
and rename DefaultClock to just Clock.
Updates #cleanup
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
This removes the unsafe/linkname and only uses the standard library.
It's a bit slower, for now, but https://go.dev/cl/518336 should get us
back.
On darwin/arm64, without https://go.dev/cl/518336
pkg: tailscale.com/tstime/mono
│ before │ after │
│ sec/op │ sec/op vs base │
MonoNow-8 16.20n ± 0% 19.75n ± 0% +21.92% (p=0.000 n=10)
TimeNow-8 39.46n ± 0% 39.40n ± 0% -0.16% (p=0.002 n=10)
geomean 25.28n 27.89n +10.33%
And with it,
MonoNow-8 16.34n ± 1% 16.93n ± 0% +3.67% (p=0.001 n=10)
TimeNow-8 39.55n ± 15% 38.46n ± 1% -2.76% (p=0.000 n=10)
geomean 25.42n 25.52n +0.41%
Updates #8839
Updates tailscale/go#70
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This change introduces tstime.Clock which is the start of a mockable
interface for use with testing other upcoming code changes.
Fixes#8463
Change-Id: I59eabc797828809194575736615535d918242ec4
Signed-off-by: Adrian Dewhurst <adrian@tailscale.com>
Calling both mono.Now() and time.Now() is slow and
leads to unnecessary precision errors.
Instead, directly compute mono.Time relative to baseMono and baseWall.
This is the opposite calculation as mono.Time.WallTime.
Updates tailscale/corp#8427
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
Add Value, which measures the rate at which an event occurs,
exponentially weighted towards recent activity.
It is guaranteed to occupy O(1) memory, operate in O(1) runtime,
and is safe for concurrent use.
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
The time.Parse function has been optimized to the point
where it is faster than our custom implementation.
See upstream changes in:
* https://go.dev/cl/429862
* https://go.dev/cl/425197
* https://go.dev/cl/425116
Performance:
BenchmarkGoParse3339/Z 38.75 ns/op 0 B/op 0 allocs/op
BenchmarkGoParse3339/TZ 54.02 ns/op 0 B/op 0 allocs/op
BenchmarkParse3339/Z 40.17 ns/op 0 B/op 0 allocs/op
BenchmarkParse3339/TZ 87.06 ns/op 0 B/op 0 allocs/op
We can see that the stdlib implementation is now faster.
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
This updates all source files to use a new standard header for copyright
and license declaration. Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.
This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.
Updates #6865
Signed-off-by: Will Norris <will@tailscale.com>
The cutset provided to strings.TrimRight was missing the digit '6',
making it such that we couldn't parse something like "365d".
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
The //go:build syntax was introduced in Go 1.17:
https://go.dev/doc/go1.17#build-lines
gofmt has kept the +build and go:build lines in sync since
then, but enough time has passed. Time to remove them.
Done with:
perl -i -npe 's,^// \+build.*\n,,' $(git grep -l -F '+build')
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This test set the bar too high.
Just a couple of missed timers was enough to fail.
Change the test to more of a sanity check.
While we're here, run it for just 1s instead of 5s.
Prior to this change, on a 13" M1 MPB, with
stress -p 512 ./rate.test -test.run=QPS
I saw 90%+ failures.
After this change, I'm at 30k runs with no failures yet.
Fixes#3733
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
This test is highly dependent on the accuracy of OS timers.
Reduce the number of failures by decreasing the required
accuracy from 0.999 to 0.995.
Also, switch from repeated time.Sleep to using a time.Ticker
for improved accuracy.
Updates #2727
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
This was the proximate cause of #2579.
#2582 is a deeper fix, but this will remain
as a footgun, so may as well fix it too.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
This is a simplified rate limiter geared for exactly our needs:
A fast, mono.Time-based rate limiter for use in tstun.
It was generated by stripping down the x/time/rate rate limiter
to just our needs and switching it to use mono.Time.
It removes one time.Now call per packet.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Package mono provides a fast monotonic time.
Its primary advantage is that it is fast:
It is approximately twice as fast as time.Now.
This is because time.Now uses two clock calls,
one for wall time and one for monotonic time.
We ask for the current time 4-6 times per network packet.
At ~50ns per call to time.Now, that's enough to show
up in CPU profiles.
Package mono is a first step towards addressing that.
It is designed to be a near drop-in replacement for package time.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
Makes parsing 4.6x faster.
name old time/op new time/op delta
ParseInt-12 32.1ns ± 1% 6.9ns ± 2% -78.55% (p=0.000 n=10+9)
Signed-off-by: David Anderson <danderson@tailscale.com>
Go's time.Parse always allocates a FixedZone for time strings not in
UTC (ending in "Z"). This avoids that allocation, at the cost of
adding a cache.
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
