Add exported global variables and store the results of benchmarked
functions in them. This prevents the current compiler optimizations
from removing the instructions that are needed to compute the return
values of the benchmarked functions.
Change-Id: If8b08424e85f3796bb6dd73e761c653abbabcc5e
Reviewed-on: https://go-review.googlesource.com/37195
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The below range loop will not stop when encountering
the first '.' character in a Darwin version string like "15.6.0".
for i = range osver {
if osver[i] != '.' {
continue
}
}
}
Therefore, the condition i > 2 was always satisfied and
supportsCloseOnExec was always set to true.
Since the minimum supported version of OSX for go is currently 10.8
and O_CLOEXEC is implemented from OSX 10.7 on the detection code
can be removed and support for O_CLOEXEC is always assumed to exist.
Change-Id: Idd10094d8385dd4adebc8d7a6d9e9a8f29455867
Reviewed-on: https://go-review.googlesource.com/37193
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The emphasize function used a complex regexp to find URLs, which
truncated some types of URL and did not match others.
This has been simplified and adjusted to allow valid punctuation
like :: or ! in the path part and :[] in the host part.
Comments were added to clarify what this regexp allows.
The path part matches query and fragment also so document this.
Removed news, telnet, wais, and prospero protocols.
Tests were added for:
IPV6 URLs
URLs surrounded by brackets
URLs containing ::
URLs containing :;!- in the path
In order to allow punctuation and yet preserve current behaviour,
URLs are not permitted to end in .,:;?! to allow the use of
normal punctuation surrounding URLs in comments.
Fixes#18139
Change-Id: I38b2d7a85fe0d171e4bf4aac420f8c2d3ced8a2f
Reviewed-on: https://go-review.googlesource.com/37192
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On AMD64 Most operation can have one operand in memory.
Combine load and dependand operation into one new operation,
where possible. I've seen no significant performance changes on go1,
but this allows to remove ~1.8kb code from go tool. And in math package
I see e. g.:
Remainder-6 70.0ns ± 0% 64.6ns ± 0% -7.76% (p=0.000 n=9+1
Change-Id: I88b8602b1d55da8ba548a34eb7da4b25d59a297e
Reviewed-on: https://go-review.googlesource.com/36793
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The type of an intermediate multiply was wrong. When that
intermediate multiply was spilled, the top 32 bits were lost.
Fixes#19153
Change-Id: Ib29350a4351efa405935b7f7ee3c112668e64108
Reviewed-on: https://go-review.googlesource.com/37212
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
- moved from: x&m>>k | x&^m<<k to: x&m>>k | x<<k&m
This permits use of the same constant m twice (*) which may be
better for machines that can't use large immediate constants
directly with an AND instruction and have to load them explicitly.
*) CPUs don't usually have a &^ instruction, so x&^m becomes x&(^m)
- simplified returns
This improves the generated code because the compiler recognizes
x>>k | x<<k as ROT when k is the bitsize of x.
The 8-bit versions of these instructions can be significantly faster
still if they are replaced with table lookups, as long as the table
is in cache. If the table is not in cache, table-lookup is probably
slower, hence the choice of an explicit register-only implementation
for now.
BenchmarkReverse-8 8.50 6.86 -19.29%
BenchmarkReverse8-8 2.17 1.74 -19.82%
BenchmarkReverse16-8 2.89 2.34 -19.03%
BenchmarkReverse32-8 3.55 2.95 -16.90%
BenchmarkReverse64-8 6.81 5.57 -18.21%
BenchmarkReverseBytes-8 3.49 2.48 -28.94%
BenchmarkReverseBytes16-8 0.93 0.62 -33.33%
BenchmarkReverseBytes32-8 1.55 1.13 -27.10%
BenchmarkReverseBytes64-8 2.47 2.47 +0.00%
Reverse-8 8.50ns ± 0% 6.86ns ± 0% ~ (p=1.000 n=1+1)
Reverse8-8 2.17ns ± 0% 1.74ns ± 0% ~ (p=1.000 n=1+1)
Reverse16-8 2.89ns ± 0% 2.34ns ± 0% ~ (p=1.000 n=1+1)
Reverse32-8 3.55ns ± 0% 2.95ns ± 0% ~ (p=1.000 n=1+1)
Reverse64-8 6.81ns ± 0% 5.57ns ± 0% ~ (p=1.000 n=1+1)
ReverseBytes-8 3.49ns ± 0% 2.48ns ± 0% ~ (p=1.000 n=1+1)
ReverseBytes16-8 0.93ns ± 0% 0.62ns ± 0% ~ (p=1.000 n=1+1)
ReverseBytes32-8 1.55ns ± 0% 1.13ns ± 0% ~ (p=1.000 n=1+1)
ReverseBytes64-8 2.47ns ± 0% 2.47ns ± 0% ~ (all samples are equal)
Change-Id: I0064de8c7e0e568ca7885d6f7064344bef91a06d
Reviewed-on: https://go-review.googlesource.com/37215
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
We can immediately emit static assignment data rather than queueing
them up to be processed during SSA building.
Passes toolstash -cmp.
Change-Id: I8bcea4b72eafb0cc0b849cd93e9cde9d84f30d5e
Reviewed-on: https://go-review.googlesource.com/37024
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The rules for folding addresses into load/stores checks sym1 is
not on stack (because the stack offset is not known at that point).
But sym1 could be nil, which invalidates the check. Check merged
sym instead.
Fixes#19137.
Change-Id: I8574da22ced1216bb5850403d8f08ec60a8d1005
Reviewed-on: https://go-review.googlesource.com/37145
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
These seem not to really matter, but good to be correct.
Change-Id: I02edb9797c3d6739725cfbe4723c75f151acd05e
Reviewed-on: https://go-review.googlesource.com/36837
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
SSA's writebarrier pass requires WB store ops are always at the
end of a block. If we move write barrier insertion into SSA and
emits normal Store ops when building SSA, this requirement becomes
impractical -- it will create too many blocks for all the Store
ops.
Redo SSA's writebarrier pass, explicitly order values in store
order, so it no longer needs this requirement.
Updates #17583.
Fixes#19067.
Change-Id: I66e817e526affb7e13517d4245905300a90b7170
Reviewed-on: https://go-review.googlesource.com/36834
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Nil check removal in the same block is disabled due to issue 18725:
because the values are not ordered, a nilcheck may influence a
value that is logically before it. This CL re-enables same-block
nilcheck removal by ordering values in store order first.
Updates #18725.
Change-Id: I287a38525230c14c5412cbcdbc422547dabd54f6
Reviewed-on: https://go-review.googlesource.com/35496
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
If the caller set ups a Credential in os/exec.Command,
os/exec.Command.Start will end up calling setgroups(2), even if no
supplementary groups were given.
Only root can call setgroups(2) on BSD kernels, which causes Start to
fail for non-root users when they try to set uid and gid for the new
process.
We fix by introducing a new field to syscall.Credential named
NoSetGroups, and setgroups(2) is only called if it is false.
We make this field with inverted logic to preserve backward
compatibility.
RELNOTES=yes
Change-Id: I3cff1f21c117a1430834f640ef21fd4e87e06804
Reviewed-on: https://go-review.googlesource.com/36697
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently the conversion from constant divides to multiplies is mostly
done during the walk pass. This is suboptimal because SSA can
determine that the value being divided by is constant more often
(e.g. after inlining).
Change-Id: If1a9b993edd71be37396b9167f77da271966f85f
Reviewed-on: https://go-review.googlesource.com/37015
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Currently, whether we need a write barrier is simply a property of the
pointer slot being written to.
The only optimization we currently apply using the value being written
is that pointers to stack variables can omit write barriers because
they're only written to stack slots... but we already omit write
barriers for all writes to the stack anyway.
Passes toolstash -cmp.
Change-Id: I7f16b71ff473899ed96706232d371d5b2b7ae789
Reviewed-on: https://go-review.googlesource.com/37109
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Suggested by Dmitry in CL 36792 review.
Clearly safe since there are many different semaRoots
that could all have profiled sudogs calling mutexevent.
Change-Id: I45eed47a5be3e513b2dad63b60afcd94800e16d1
Reviewed-on: https://go-review.googlesource.com/37104
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Also runs 100X faster on average, because it takes so many
fewer attempts to trigger the failure.
Fixes#11443.
Change-Id: I8c39ee48bb3ff6c36fa63083e04076771b65a80d
Reviewed-on: https://go-review.googlesource.com/36841
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
For #10776.
Change-Id: Id64a7e35c7cdcd9be16cbe3358402fa379090e36
Reviewed-on: https://go-review.googlesource.com/36975
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is what gcc does when it generates object files.
And it is easier to count everything, when it starts from 0.
Make go linker do the same.
gcc also does not output IMAGE_OPTIONAL_HEADER or
PE64_IMAGE_OPTIONAL_HEADER for object files.
Perhaps we should do the same, but not in this CL.
For #10776.
Change-Id: I9789c337648623b6cfaa7d18d1ac9cef32e180dc
Reviewed-on: https://go-review.googlesource.com/36974
Reviewed-by: Ian Lance Taylor <iant@golang.org>
For #10776.
Change-Id: I7931558257c1f6b895e4d44b46d320a54de0d677
Reviewed-on: https://go-review.googlesource.com/36973
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Fixes#19114.
Change-Id: I352add53d6ee8bf78792564225099f8537ac6b46
Reviewed-on: https://go-review.googlesource.com/37106
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: David du Colombier <0intro@gmail.com>
This change removes the punitive language and anonymous reporting mechanism
from the Code of Conduct document. Read on for the rationale.
More than a year has passed since the Go Code of Conduct was introduced.
In that time, there have been a small number (<30) of reports to the Working Group.
Some reports we handled well, with positive outcomes for all involved.
A few reports we handled badly, resulting in hurt feelings and a bad
experience for all involved.
On reflection, the reports that had positive outcomes were ones where the
Working Group took the role of advisor/facilitator, listening to complaints and
providing suggestions and advice to the parties involved.
The reports that had negative outcomes were ones where the subject of the
report felt threatened by the Working Group and Code of Conduct.
After some discussion among the Working Group, we saw that we are most
effective as facilitators, rather than disciplinarians. The various Go spaces
already have moderators; this change to the CoC acknowledges their authority
and places the group in a purely advisory role. If an incident is
reported to the group we may provide information to or make a
suggestion the moderators, but the Working Group need not (and should not) have
any authority to take disciplinary action.
In short, we want it to be clear that the Working Group are here to help
resolve conflict, period.
The second change made here is the removal of the anonymous reporting mechanism.
To date, the quality of anonymous reports has been low, and with no way to
reach out to the reporter for more information there is often very little we
can do in response. Removing this one-way reporting mechanism strengthens the
message that the Working Group are here to facilitate a constructive dialogue.
Change-Id: Iee52aff5446accd0dae0c937bb3aa89709ad5fb4
Reviewed-on: https://go-review.googlesource.com/37014
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
I don't know why it is not working. Filed issue 19111 for this.
Fixes build.
Update #19111.
Change-Id: I76f8d6aafba5951da2f3ad7d10960419cca7dd1f
Reviewed-on: https://go-review.googlesource.com/37092
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It can't work since Plan 9 does not support the runtime poller.
Fixes build.
Change-Id: I9ec33eb66019d9364c6ff6519b61b32e59498559
Reviewed-on: https://go-review.googlesource.com/37091
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
We have seen one instance of a production job suddenly spinning to
100% CPU and becoming unresponsive. In that one instance, a SIGQUIT
was sent after 328 minutes of spinning, and the stacks showed a single
goroutine in "IO wait (scan)" state.
Looking for things that might get stuck if a goroutine got stuck in
scanning a stack, we found that injectglist does:
lock(&sched.lock)
var n int
for n = 0; glist != nil; n++ {
gp := glist
glist = gp.schedlink.ptr()
casgstatus(gp, _Gwaiting, _Grunnable)
globrunqput(gp)
}
unlock(&sched.lock)
and that casgstatus spins on gp.atomicstatus until the _Gscan bit goes
away. Essentially, this code locks sched.lock and then while holding
sched.lock, waits to lock gp.atomicstatus.
The code that is doing the scan is:
if castogscanstatus(gp, s, s|_Gscan) {
if !gp.gcscandone {
scanstack(gp, gcw)
gp.gcscandone = true
}
restartg(gp)
break loop
}
More analysis showed that scanstack can, in a rare case, end up
calling back into code that acquires sched.lock. For example:
runtime.scanstack at proc.go:866
calls runtime.gentraceback at mgcmark.go:842
calls runtime.scanstack$1 at traceback.go:378
calls runtime.scanframeworker at mgcmark.go:819
calls runtime.scanblock at mgcmark.go:904
calls runtime.greyobject at mgcmark.go:1221
calls (*runtime.gcWork).put at mgcmark.go:1412
calls (*runtime.gcControllerState).enlistWorker at mgcwork.go:127
calls runtime.wakep at mgc.go:632
calls runtime.startm at proc.go:1779
acquires runtime.sched.lock at proc.go:1675
This path was found with an automated deadlock-detecting tool.
There are many such paths but they all go through enlistWorker -> wakep.
The evidence strongly suggests that one of these paths is what caused
the deadlock we observed. We're running those jobs with
GOTRACEBACK=crash now to try to get more information if it happens
again.
Further refinement and analysis shows that if we drop the wakep call
from enlistWorker, the remaining few deadlock cycles found by the tool
are all false positives caused by not understanding the effect of calls
to func variables.
The enlistWorker -> wakep call was intended only as a performance
optimization, it rarely executes, and if it does execute at just the
wrong time it can (and plausibly did) cause the deadlock we saw.
Comment it out, to avoid the potential deadlock.
Fixes#19112.
Unfixes #14179.
Change-Id: I6f7e10b890b991c11e79fab7aeefaf70b5d5a07b
Reviewed-on: https://go-review.googlesource.com/37093
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This adds more information to the pkg stale reason for debugging
purposes.
Change-Id: I7b626db4520baa1127195ae859f4da9b49304636
Reviewed-on: https://go-review.googlesource.com/36944
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This changes the os package to use the runtime poller for file I/O
where possible. When a system call blocks on a pollable descriptor,
the goroutine will be blocked on the poller but the thread will be
released to run other goroutines. When using a non-pollable
descriptor, the os package will continue to use thread-blocking system
calls as before.
For example, on GNU/Linux, the runtime poller uses epoll. epoll does
not support ordinary disk files, so they will continue to use blocking
I/O as before. The poller will be used for pipes.
Since this means that the poller is used for many more programs, this
modifies the runtime to only block waiting for the poller if there is
some goroutine that is waiting on the poller. Otherwise, there is no
point, as the poller will never make any goroutine ready. This
preserves the runtime's current simple deadlock detection.
This seems to crash FreeBSD systems, so it is disabled on FreeBSD.
This is issue 19093.
Using the poller on Windows requires opening the file with
FILE_FLAG_OVERLAPPED. We should only do that if we can remove that
flag if the program calls the Fd method. This is issue 19098.
Update #6817.
Update #7903.
Update #15021.
Update #18507.
Update #19093.
Update #19098.
Change-Id: Ia5197dcefa7c6fbcca97d19a6f8621b2abcbb1fe
Reviewed-on: https://go-review.googlesource.com/36800
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
We did not create it. We should not delete it.
Change-Id: If98454ab233ce25367e11a7c68d31b49074537dd
Reviewed-on: https://go-review.googlesource.com/37030
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
