To avoid memory leaks in slices that contain pointers, clear the elements between the new length and the original length.
Fixes#63393
Change-Id: Ic65709726f4479d70c6bce14aa367feb753d41da
Reviewed-on: https://go-review.googlesource.com/c/go/+/541477
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Follow-up on CL 539299: missed to incorporate the updated
comment per feedback on that CL.
For #50489.
Change-Id: Ib035400038b1d11532f62055b5cdb382ab75654c
Reviewed-on: https://go-review.googlesource.com/c/go/+/542115
Run-TryBot: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
dynimports is a leftover from a previous implementation, so remove it
for now.
Change-Id: I6419e3fa35ce6a9e46aa387377e436415221e3a2
GitHub-Last-Rev: ba429bfb12
GitHub-Pull-Request: golang/go#64097
Reviewed-on: https://go-review.googlesource.com/c/go/+/541895
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
After landing the new execution tracer, the Windows builders failed with
some new errors.
Currently the GoSyscallBegin event has no indicator that its the target
of a ProcSteal event. This can lead to an ambiguous situation that is
unresolvable if timestamps are broken. For instance, if the tracer sees
the ProcSteal event while a goroutine has been observed to be in a
syscall (one that, for instance, did not actually lose its P), it will
proceed with the ProcSteal incorrectly.
This is a little abstract. For a more concrete example, see the
go122-syscall-steal-proc-ambiguous test.
This change resolves this ambiguity by interleaving GoSyscallBegin
events into how Ps are sequenced. Because a ProcSteal has a sequence
number (it has to, it's stopping a P from a distance) it necessarily
has to synchronize with a precise ProcStart event. This change basically
just extends this synchronization to GoSyscallBegin, so the ProcSteal
can't advance until _exactly the right_ syscall has been entered.
This change removes the test skip, since it and CL 541695 fix the two
main issues observed on Windows platforms.
For #60773.
Fixes#64061.
Change-Id: I069389cd7fe1ea903edf42d79912f6e2bcc23f62
Reviewed-on: https://go-review.googlesource.com/c/go/+/541696
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
An out-of-memory error in this test has been observed on 32-bit
platforms, so halve the memory footprint of the test. Also halve the
size of steady-state allocation rate in bytes. The end result should be
approximately the same GC CPU load but at half the memory usage.
Change-Id: I2c2d335da7dc4c5c58cb9d92b6e5a4ece55d24a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/542215
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Currently the trace parser enforces that the timestamps for a series of
a batches on the same M come in order. We cannot actually assume this in
general because we don't trust timestamps. The source of truth on the
batch order is the order in which they were emitted. If that's wrong, it
should quickly become evident in the trace.
For #60773.
For #64061.
Change-Id: I7d5a407c9568dd1ce0b79d51b2b538ed6072b26d
Reviewed-on: https://go-review.googlesource.com/c/go/+/541695
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
CL 541737 added gotypesalias to control whether Alias types are used.
This setting is meant to use by end users through go/types. However,
types2 also uses it, but it's an internal package, causing bootstrap
failed because of unknown setting.
Marking the setting as undocumented in types2 fixes the problem.
Fixes#64106
Change-Id: If51a63cb7a21d9411cd9cf81bca2530c476d22f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/542135
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Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Even though we don't issue beta pre-releases of Go at this time,
it can still be useful to build them without publishing as part
of testing the release infrastructure.
For such versions, use the next directory content so that the
API check doesn't produce a false positive during the earlier
stages of the development cycle, before the next directory is
merged into a combined and eventually frozen api file.
For #29205.
Change-Id: Ib5e962670de1df22f7df64dd237b555953096808
Reviewed-on: https://go-review.googlesource.com/c/go/+/542000
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Make sure the FileVersions map is populated in test runs.
For #62605.
Change-Id: I06585b5110a4a98b577edb8e03a4981b2484a5a4
Reviewed-on: https://go-review.googlesource.com/c/go/+/541736
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Most of the uses of work.pauseStart are completely useless, it could
simply be a local variable. One use passes a parameter from gcMarkDone
to gcMarkTermination, but that could simply be an argument.
Keeping this field in workType makes it seems more important than it
really is, so just drop it.
Change-Id: I2fdc0b21f8844e5e7be47148c3e10f13e49815c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/542075
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Generate the CC version of many opcodes whose result is compared against
signed 0. The approach taken here works even if the opcode result is used in
multiple places too.
Add support for ADD, ADDconst, ANDN, SUB, NEG, CNTLZD, NOR conversions
to their CC opcode variant. These are the most commonly used variants.
Also, do not set clobberFlags of CNTLZD and CNTLZW, they do not clobber
flags.
This results in about 1% smaller text sections in kubernetes binaries,
and no regressions in the crypto benchmarks.
Change-Id: I9e0381944869c3774106bf348dead5ecb96dffda
Reviewed-on: https://go-review.googlesource.com/c/go/+/538636
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
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Reviewed-by: Jayanth Krishnamurthy <jayanth.krishnamurthy@ibm.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
This CL exports the previously unexported Alias type and
corresponding functions and methods per issue #63223.
Whether Alias types are used or not is controlled by
the gotypesalias setting with the GODEBUG environment
variable. Setting gotypesalias to "1" enables the Alias
types:
GODEBUG=gotypesalias=1
By default, gotypesalias is not set.
Adjust test cases that enable/disable the use of Alias
types to use -gotypesalias=1 or -gotypesalias=0 rather
than -alias and -alias=false for consistency and to
avoid confusion.
For #63223.
Change-Id: I51308cad3320981afac97dd8c6f6a416fdb0be55
Reviewed-on: https://go-review.googlesource.com/c/go/+/541737
Run-TryBot: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
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Reviewed-by: Robert Griesemer <gri@google.com>
As of CL 539699, PGO-based devirtualization supports devirtualization of
function values in addition to interface method calls. As with CL
497175, we need to explicitly look up functions from export data that
may not be imported already.
Symbol naming is ambiguous (`foo.Bar.func1` could be a closure or a
method), so we simply attempt to do both types of lookup. That said,
closures are defined in export data only as OCLOSURE nodes in the
enclosing function, which this CL does not yet attempt to expand.
For #61577.
Change-Id: Ic7205b046218a4dfb8c4162ece3620ed1c3cb40a
Reviewed-on: https://go-review.googlesource.com/c/go/+/540258
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Today, PGO-based devirtualization only applies to interface calls. This
CL extends initial support to function values (i.e., function/closure
pointers passed as arguments or stored in a struct).
This CL is a minimal implementation with several limitations.
* Export data lookup of function value callees not implemented
(equivalent of CL 497175; done in CL 540258).
* Callees must be standard static functions. Callees that are closures
(requiring closure context) are not supported.
For #61577.
Change-Id: I7d328859035249e176294cd0d9885b2d08c853f6
Reviewed-on: https://go-review.googlesource.com/c/go/+/539699
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Replace calls to pkgNameOf with calls to types2.Info.PkgNameOf.
Delete function pkgNameOf and file decl.go which are not needed anymore.
For #62037
Change-Id: Ib8a0411cc9eb9fdd42ee6e73c23deed2daaf73d5
GitHub-Last-Rev: 3c8928fb51
GitHub-Pull-Request: golang/go#64075
Reviewed-on: https://go-review.googlesource.com/c/go/+/541738
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Robert Griesemer <gri@google.com>
Run-TryBot: qiulaidongfeng <2645477756@qq.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
These functions acquire the heap lock. If they're not called on the
systemstack, a stack growth could cause a self-deadlock since stack
growth may allocate memory from the page heap.
This has been a problem for a while. If this is what's plaguing the
ppc64 port right now, it's very surprising (and probably just
coincidental) that it's showing up now.
For #64050.
For #64062.
Fixes#64067.
Change-Id: I2b95dc134d17be63b9fe8f7a3370fe5b5438682f
Reviewed-on: https://go-review.googlesource.com/c/go/+/541635
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
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Auto-Submit: Michael Knyszek <mknyszek@google.com>
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Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Paul Murphy <murp@ibm.com>
For #62037.
Change-Id: I354f6417232708278d3f2b2d5ea41ff48e08d6b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/541575
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>
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Run-TryBot: Robert Griesemer <gri@google.com>
In manual mode, _Alias nodes are disabled by default and can be
enabled with a line comment (// -alias) at the start of a file.
Follow-up on feedback for CL 521956.
Change-Id: I937eb2e58e9e96fa6785ac45ca19e6328d2bd1fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/541295
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
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CL 539699 will need to do the equivalent of
internal/abi.FuncPCABIInternal to get the PC of a function value for the
runtime devirtualization check.
Move the FuncPC expression creation from the depths of walk to a
typecheck helper so it can be reused in both places.
For #61577.
Change-Id: I76f333157cf0e5fd867b41bfffcdaf6f45254707
Reviewed-on: https://go-review.googlesource.com/c/go/+/539698
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
There are a couple known issues here. Disable the tests for now so it's
not blocking anyone.
For #64061.
Change-Id: Iaaa9007b93ea78739cb7d2b59b2a1715de29d72b
Reviewed-on: https://go-review.googlesource.com/c/go/+/541197
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Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
For #63960.
Change-Id: I1efe35435e32623aba894a915114e394570ebc56
Reviewed-on: https://go-review.googlesource.com/c/go/+/540259
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This change adds a new MutatorUtilization for traces for Go 1.22+.
To facilitate testing, it also generates a short trace with the
gc-stress.go test program (shortening its duration to 10ms) and adds it
to the tests for the internal/trace/v2 package. Notably, we make sure
this trace has a GCMarkAssistActive event to test that codepath.
For #63960.
For #60773.
Change-Id: I2e61f545988677be716818e2a08641c54c4c201f
Reviewed-on: https://go-review.googlesource.com/c/go/+/540256
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
This change mostly implements the design described in #60773 and
includes a new scalable parser for the new trace format, available in
internal/trace/v2. I'll leave this commit message short because this is
clearly an enormous CL with a lot of detail.
This change does not hook up the new tracer into cmd/trace yet. A
follow-up CL will handle that.
For #60773.
Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64-longtest,gotip-linux-amd64-longtest-race
Change-Id: I5d2aca2cc07580ed3c76a9813ac48ec96b157de0
Reviewed-on: https://go-review.googlesource.com/c/go/+/494187
Reviewed-by: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Currently the user arena code writes heap bits to the (*mspan).heapBits
space with the platform-specific byte ordering (the heap bits are
written and managed as uintptrs). However, the compiler always emits GC
metadata for types in little endian.
Because the scanning part of the code that loads through the type
pointer in the allocation header expects little endian ordering, we end
up with the wrong byte ordering in GC when trying to scan arena memory.
Fix this by writing out the user arena heap bits in little endian on big
endian platforms.
This means that the space returned by (*mspan).heapBits has a different
meaning for user arenas and small object spans, which is a little odd,
so I documented it. To reduce the chance of misuse of the writeHeapBits
API, which now writes out heap bits in a different ordering than
writeSmallHeapBits on big endian platforms, this change also renames
writeHeapBits to writeUserArenaHeapBits.
Much of this can be avoided in the future if the compiler were to write
out the pointer/scalar bits as an array of uintptr values instead of
plain bytes. That's too big of a change for right now though.
This change is a no-op on little endian platforms. I confirmed it by
checking for any assembly code differences in the runtime test binary.
There were none. With this change, the arena tests pass on ppc64.
Fixes#64048.
Change-Id: If077d003872fcccf5a154ff5d8441a58582061bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/541315
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This CL changes the FileVersions map to map to version strings
rather than Version structs, for use with the new go/versions
package.
Adjust the cmd/dist bootstrap package list to include go/version.
Adjust the compiler's noder to work with the new API.
For #62605.
For #63974.
Change-Id: I191a7015ba3fb61c646e9f9d3c3dbafc9653ccb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/541296
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
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While fixing several bugs in path handling on Windows,
beginning with \\?\.
Prior to #540277, VolumeName considered the first path component
after the \\?\ prefix to be part of the volume name.
After, it considered only the \\? prefix to be the volume name.
Restore the previous behavior.
Fixes#64028
Change-Id: I6523789e61776342800bd607fb3f29d496257e68
Reviewed-on: https://go-review.googlesource.com/c/go/+/541175
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Currently tickspersecond forces a 100 millisecond sleep the first time
it's called. This isn't great for profiling short-lived programs, since
both CPU profiling and block profiling might call into it.
100 milliseconds is a long time, but it's chosen to try and capture a
decent estimate of the conversion on platform with course-granularity
clocks. If the granularity is 15 ms, it'll only be 15% off at worst.
Let's try a different strategy. First, let's require 5 milliseconds of
time to have elapsed at a minimum. This should be plenty on platforms
with nanosecond time granularity from the system clock, provided the
caller of tickspersecond intends to use it for calculating durations,
not timestamps. Next, grab a timestamp as close to process start as
possible, so that we can cover some of that 5 millisecond just during
runtime start.
Finally, this function is only ever called from normal goroutine
contexts. Let's do a regular goroutine sleep instead of a thread-level
sleep under a runtime lock, which has all sorts of nasty effects on
preemption.
While we're here, let's also rename tickspersecond to ticksPerSecond.
Also, let's write down some explicit rules of thumb on when to use this
function. Clocks are hard, and using this for timestamp conversion is
likely to make lining up those timestamps with other clocks on the
system difficult if not impossible.
Note that while this improves ticksPerSecond on platforms with good
clocks, we still end up with a pretty coarse sleep on platforms with
coarse clocks, and a pretty coarse result. On these platforms, keep the
minimum required elapsed time at 100 ms. There's not much we can do
about these platforms except spin and try to catch the clock boundary,
but at 10+ ms of granularity, that might be a lot of spinning.
Fixes#63103.
Fixes#63078.
Change-Id: Ic32a4ba70a03bdf5c13cb80c2669c4064aa4cca2
Reviewed-on: https://go-review.googlesource.com/c/go/+/538898
Auto-Submit: Michael Knyszek <mknyszek@google.com>
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Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Currently dedicated GC mark workers really try to avoid getting
preempted. The one exception is for a pending STW, indicated by
sched.gcwaiting. This is currently fine because other kinds of
preemptions don't matter to the mark workers: they're intentionally
bound to their P.
With the new execution tracer we're going to want to use forEachP to get
the attention of all Ps. We may want to do this during a GC cycle.
forEachP doesn't set sched.gcwaiting, so it may end up waiting the full
GC mark phase, burning a thread and a P in the meantime. This can mean
basically seconds of waiting and trying to preempt GC mark workers.
This change makes all mark workers yield if (*p).runSafePointFn != 0 so
that the workers actually yield somewhat promptly in response to a
forEachP attempt.
Change-Id: I7430baf326886b9f7a868704482a224dae7c9bba
Reviewed-on: https://go-review.googlesource.com/c/go/+/537235
Reviewed-by: Michael Pratt <mpratt@google.com>
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Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Currently any thread that tries to get the attention of all Ps (e.g.
stopTheWorldWithSema and forEachP) ends up in a non-preemptible state
waiting to preempt another thread. Thing is, that other thread might
also be in a non-preemptible state, trying to preempt the first thread,
resulting in a deadlock.
This is a general problem, but in practice it only boils down to one
specific scenario: a thread in GC is blocked trying to preempt a
goroutine to scan its stack while that goroutine is blocked in a
non-preemptible state to get the attention of all Ps.
There's currently a hack in a few places in the runtime to move the
calling goroutine into _Gwaiting before it goes into a non-preemptible
state to preempt other threads. This lets the GC scan its stack because
the goroutine is trivially preemptible. The only restriction is that
forEachP and stopTheWorldWithSema absolutely cannot reference the
calling goroutine's stack. This is generally not necessary, so things
are good.
Anyway, to avoid exposing the details of this hack, this change creates
a safer wrapper around forEachP (and then renames it to forEachP and the
existing one to forEachPInternal) that performs the goroutine status
change, just like stopTheWorld does. We're going to need to use this
hack with forEachP in the new tracer, so this avoids propagating the
hack further and leaves it as an implementation detail.
Change-Id: I51f02e8d8e0a3172334d23787e31abefb8a129ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/533455
Auto-Submit: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Currently the execution tracer synchronizes with itself using very
heavyweight operations. As a result, it's totally fine for most of the
tracer code to look like:
if traceEnabled() {
traceXXX(...)
}
However, if we want to make that synchronization more lightweight (as
issue #60773 proposes), then this is insufficient. In particular, we
need to make sure the tracer can't observe an inconsistency between g
atomicstatus and the event that would be emitted for a particular
g transition. This means making the g status change appear to happen
atomically with the corresponding trace event being written out from the
perspective of the tracer.
This requires a change in API to something more like a lock. While we're
here, we might as well make sure that trace events can *only* be emitted
while this lock is held. This change introduces such an API:
traceAcquire, which returns a value that can emit events, and
traceRelease, which requires the value that was returned by
traceAcquire. In practice, this won't be a real lock, it'll be more like
a seqlock.
For the current tracer, this API is completely overkill and the value
returned by traceAcquire basically just checks trace.enabled. But it's
necessary for the tracer described in #60773 and we can implement that
more cleanly if we do this refactoring now instead of later.
For #60773.
Change-Id: Ibb9ff5958376339fafc2b5180aef65cf2ba18646
Reviewed-on: https://go-review.googlesource.com/c/go/+/515635
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Change-Id: I3a6cded573aa35afe8abc624c78599f03ec8bf94
Reviewed-on: https://go-review.googlesource.com/c/go/+/538217
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This change replaces the 1-bit-per-word heap bitmap for most size
classes with allocation headers for objects that contain pointers. The
header consists of a single pointer to a type. All allocations with
headers are treated as implicitly containing one or more instances of
the type in the header.
As the name implies, headers are usually stored as the first word of an
object. There are two additional exceptions to where headers are stored
and how they're used.
Objects smaller than 512 bytes do not have headers. Instead, a heap
bitmap is reserved at the end of spans for objects of this size. A full
word of overhead is too much for these small objects. The bitmap is of
the same format of the old bitmap, minus the noMorePtrs bits which are
unnecessary. All the objects <512 bytes have a bitmap less than a
pointer-word in size, and that was the granularity at which noMorePtrs
could stop scanning early anyway.
Objects that are larger than 32 KiB (which have their own span) have
their headers stored directly in the span, to allow power-of-two-sized
allocations to not spill over into an extra page.
The full implementation is behind GOEXPERIMENT=allocheaders.
The purpose of this change is performance. First and foremost, with
headers we no longer have to unroll pointer/scalar data at allocation
time for most size classes. Small size classes still need some
unrolling, but their bitmaps are small so we can optimize that case
fairly well. Larger objects effectively have their pointer/scalar data
unrolled on-demand from type data, which is much more compactly
represented and results in less TLB pressure. Furthermore, since the
headers are usually right next to the object and where we're about to
start scanning, we get an additional temporal locality benefit in the
data cache when looking up type metadata. The pointer/scalar data is
now effectively unrolled on-demand, but it's also simpler to unroll than
before; that unrolled data is never written anywhere, and for arrays we
get the benefit of retreading the same data per element, as opposed to
looking it up from scratch for each pointer-word of bitmap. Lastly,
because we no longer have a heap bitmap that spans the entire heap,
there's a flat 1.5% memory use reduction. This is balanced slightly by
some objects possibly being bumped up a size class, but most objects are
not tightly optimized to size class sizes so there's some memory to
spare, making the header basically free in those cases.
See the follow-up CL which turns on this experiment by default for
benchmark results. (CL 538217.)
Change-Id: I4c9034ee200650d06d8bdecd579d5f7c1bbf1fc5
Reviewed-on: https://go-review.googlesource.com/c/go/+/437955
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
This change adds the allocation headers GOEXPERIMENT which is a no-op.
It forks two runtime files temporarily to make the GOEXPERIMENT easier
to maintain. The forked files are mbitmap.go and msize.go.
Change-Id: I60202c00e614e4517de7dd000029cf80dd0121ef
Reviewed-on: https://go-review.googlesource.com/c/go/+/537980
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Adds the CertPool method AddCertWithConstraint, which allows adding a
certificate to a pool with an arbitrary constraint which cannot be
otherwise expressed in the certificate.
Fixes#57178
Change-Id: Ic5b0a22a66aefa5ba5d8ed5ef11389996b59862b
Reviewed-on: https://go-review.googlesource.com/c/go/+/519315
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Tatiana Bradley <tatianabradley@google.com>
Run-TryBot: Roland Shoemaker <roland@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Temporarily skip to make the builder happy. Will work on a fix.
Updates #63938.
Change-Id: Ic9db771342108430c29774b2c3e50043791189a6
Reviewed-on: https://go-review.googlesource.com/c/go/+/541195
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cherry Mui <cherryyz@google.com>
The Go linker doesn't currently merge .pdata/.xdata sections from the
host object files generated by the C compiler when using internal
linking. This means that the stack can't be unwind in C -> Go.
This CL fixes that and adds a test to ensure that the stack can be
unwind in C -> Go and Go -> C transitions, which was not well tested.
Updates #57302
Change-Id: Ie86a5e6e30b80978277e66ccc2c48550e51263c8
Reviewed-on: https://go-review.googlesource.com/c/go/+/534555
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>
This is a followup to CL 14177. It applies copyBufPool optimization to
transferWriter.doBodyCopy(). The function is used every time Request or
Response is written.
Without this patch for every Request and Response processed, if there is
a body, we need to allocate and GC a 32k buffer. This is quickly causing
GC pressure.
Fixes#57202
Change-Id: I4c30e1737726ac8d9937846106efd02effbae300
GitHub-Last-Rev: 908573cdbe
GitHub-Pull-Request: golang/go#57205
Reviewed-on: https://go-review.googlesource.com/c/go/+/456435
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: qiulaidongfeng <2645477756@qq.com>
This optab matching rule was used to match signed 16 bit values shifted
left by 16 bits. Unsigned 16 bit values greater than 0x7FFF<<16 were
classified as C_U32CON which led to larger than necessary codegen.
Instead, rewrite logical/arithmetic operations in the preprocessor pass
to use the 16 bit shifted immediate operation (e.g ADDIS vs ADD). This
simplifies the optab matching rules, while also minimizing codegen size
for large unsigned values.
Note, ADDIS sign-extends the constant argument, all others do not.
For matching opcodes, this means:
MOVD $is<<16,Rx becomes ADDIS $is,Rx or ORIS $is,Rx
MOVW $is<<16,Rx becomes ADDIS $is,Rx
ADD $is<<16,[Rx,]Ry becomes ADDIS $is[Rx,]Ry
OR $is<<16,[Rx,]Ry becomes ORIS $is[Rx,]Ry
XOR $is<<16,[Rx,]Ry becomes XORIS $is[Rx,]Ry
Change-Id: I1a988d9f52517a04bb8dc2e41d7caf3d5fff867c
Reviewed-on: https://go-review.googlesource.com/c/go/+/536735
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
This change introduces a new (unexported for now) _Alias type node
which serves as an explicit representation for alias types in type
alias declarations:
type A = T
The _Alias node stands for the type A in this declaration, with
the _Alias' actual type pointing to (the type node for) T.
Without the _Alias node, (the object for) A points directly to T.
Explicit _Alias nodes permit better error messages (they mention
A instead of T if the type in the source was named A) and can help
with certain type cycle problems. They are also needed to hold
type parameters for alias types, eventually.
Because an _Alias node is simply an alternative representation for
an aliased type, code that makes type-specific choices must always
look at the actual (unaliased) type denoted by a type alias.
The new function
func _Unalias(t Type) Type
performs the necessary indirection. Type switches that consider
type nodes, must either switch on _Unalias(typ) or handle the
_Alias case.
To avoid breaking clients, _Alias nodes must be enabled explicitly,
through the new Config flag _EnableAlias.
To run tests with the _EnableAlias set, use the new -alias flag as
in "go test -run short -alias". The testing harness understands
the flag as well and it may be used to enable/disable _Alias nodes
on a per-file basis, with a comment ("// -alias" or // -alias=false)
on the first line in those files. The file-based flag overrides the
command-line flag.
The use of _Alias nodes is disabled by default and must be enabled
by setting _EnableAlias.
Passes type checker tests with and without -alias flag set.
For #25838.
For #44410.
For #46477.
Change-Id: I78e178a1aef4d7f325088c0c6cbae4cfb1e5fb5c
Reviewed-on: https://go-review.googlesource.com/c/go/+/521956
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Robert Findley <rfindley@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Griesemer <gri@google.com>
Description in accordance with RFC 8878 3.1.1.3.1.6.
The decompressed size of each stream is equal to (Regenerated_Size+3)/4,
except for the last stream, which may be up to 3 bytes smaller,
to reach a total decompressed size as specified in Regenerated_Size.
Fixes#63824
Change-Id: I5a8b482a995272aa2028a81a4db86c21b1770432
GitHub-Last-Rev: 76a70756bc
GitHub-Pull-Request: golang/go#63959
Reviewed-on: https://go-review.googlesource.com/c/go/+/540055
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Klaus Post <klauspost@gmail.com>
Run-TryBot: Jes Cok <xigua67damn@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Use ADD with constants, instead of ADDI. Also use SUB with a positive constant
rather than ADD with a negative constant. The resulting assembly is still the
same.
Change-Id: Ife10bf5ae4122e525f0e7d41b5e463e748236a9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/540136
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: M Zhuo <mzh@golangcn.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Mark Ryan <markdryan@rivosinc.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Joel Sing <joel@sing.id.au>
Currently, instruction validation failure will result in a panic during
encoding. Furthermore, the errors generated do not include the PC or
file/line information that is normally present.
Fix this by:
- Tracking and printing the *obj.Prog associated with the instruction,
including the assembly instruction/opcode if it differs. This provides
the standard PC and file/line prefix, which is also expected by assembly
error end-to-end tests.
- Not proceeding with assembly if errors exist - with the current design,
errors are identified during validation, which is run via preprocess.
Attempts to encode invalid instructions will intentionally panic.
Add some additional riscv64 encoding errors, now that we can actually do so.
Change-Id: I64a7b83680c4d12aebdc96c67f9df625b5ef90d3
Reviewed-on: https://go-review.googlesource.com/c/go/+/523459
Run-TryBot: Joel Sing <joel@sing.id.au>
Reviewed-by: Mark Ryan <markdryan@rivosinc.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: M Zhuo <mzh@golangcn.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: M Zhuo <mzh@golangcn.org>
