Now a zip.Reader (an open zip file) can be passed to code
that accepts a file system, such as (soon) template parsing.
For #41190.
Change-Id: If51b12e39db3ccc27f643c2453d3300a38035360
Reviewed-on: https://go-review.googlesource.com/c/go/+/243937
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Add Stat helper function, StatFS interface, and test.
Add Stat method to fstest.MapFS.
Add testing of Stat method to fstest.TestFS.
For #41190.
Change-Id: Icf8b6eb1c3fa6f93a9be8405ec5a9468fb1da97b
Reviewed-on: https://go-review.googlesource.com/c/go/+/243913
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
It will inevitably be important to be able to pass an operating system
directory to code written to expect an fs.FS.
os.DirFS provides the conversion.
For #41190.
Change-Id: Id1a8fcbe4c7a30de2c47dea0504e9481a88b1b39
Reviewed-on: https://go-review.googlesource.com/c/go/+/243911
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
This change adds basic test helpers for file system code.
The type MapFS is a simple map-based file system for use when
exercising general file system code.
The func TestFS tests a file system implementation.
For #41190.
Change-Id: I5a2036f57e733915ad508651ad7317749794423c
Reviewed-on: https://go-review.googlesource.com/c/go/+/243910
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Rename the assembler "-compilingRuntime" flag to "-compiling-runtime",
to be more consistent with the flag style of other Go commands.
Change-Id: I8cc5cbf0b9b34d1dd4e9fa499d3fec8c1ef10b6e
Reviewed-on: https://go-review.googlesource.com/c/go/+/263857
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Because the "ios" build constraint implies "darwin", it is already
included in the general "darwin" flakiness workaround in
cmd/go/internal/robustio. We just need to relax the renameio test
to avoid false-positives there.
I do not expect this change to drive the rate of false-positives down
to zero, but it should at least reduce noise on the build dashboard.
For #42066
Change-Id: Ia33dbd33295fce5b3261b4831f2807ce29b82e65
Reviewed-on: https://go-review.googlesource.com/c/go/+/263777
Trust: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Currently the scavenging tests implicitly assume that the system huge
page size is always strictly less than 4 MiB, or pallocChunkBytes. This
leads to failures on systems with huge pages of this size, and larger.
Filter out those tests on such platforms and add a test for the 4 MiB
case. The scavenger is already equipped to handle this case.
Huge page sizes > 4 MiB are effectively ignored, so also add a test case
to ensure that happens.
Unfortunately we can't actually run these tests in our CI because they
require the platform to provide the right huge page size, but we really
should just parameterize this value so we can test it (there's a TODO
about this already).
Fixes#42053.
Change-Id: Ia576cbf67e178a14a178a893967efbed27d6eb17
Reviewed-on: https://go-review.googlesource.com/c/go/+/263837
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Trust: Michael Knyszek <mknyszek@google.com>
That is, the following two pieces of shell code are now equivalent:
$ go tool buildid $(go list -export -f {{.Export}} strings)
v_0VqA6yzwuMg2dn4u57/PXcIR2Pb8Mi9yRdcdkwe
$ go list -export -f {{.BuildID}} strings
v_0VqA6yzwuMg2dn4u57/PXcIR2Pb8Mi9yRdcdkwe
This does not expose any information that wasn't available before, but
makes this workflow simpler and faster. In the first example, we have to
execute two programs, and 'go tool buildid' has to re-open the export
data file to read the build ID.
With the new mechanism, 'go list -export' already has the build ID
ready, so we can simply print it out. Moreover, when listing lots of
related packages like './...', we can now obtain all their build IDs at
once.
Fixes#37281.
Change-Id: I8e2f65a08391b3df1a628c6e06e708b8c8cb7865
Reviewed-on: https://go-review.googlesource.com/c/go/+/263542
Trust: Daniel Martí <mvdan@mvdan.cc>
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
When cpu_no_init.go was created most architectures did not have
code in the doinit function. Currently only mips(le), riscv64 and
wasm do not have empty doinit functions.
Keeping cpu_no_init.go around does not reduce the work to satisfy
the build process when adding support for new architectures.
To support a new architecture a new file or build directive has to
be added to an existing file at any rate to define the constant
CacheLinePadSize. A new empty doinit can then be created in the
new file or the existing doinit can be reused when adding the
additional build directive.
Change-Id: I58a97f8cdf1cf1be85c37f4550c40750358aa031
Reviewed-on: https://go-review.googlesource.com/c/go/+/263801
Trust: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
This makes the behavior of the cgi package on NetBSD consistent with its
behavior on the other BSDs. It is also necessary for the test suite to
pass on NetBSD with gccgo (see CL 261137).
Change-Id: I531a6e0954f895a921204dcc61e3f3e90860a23d
Reviewed-on: https://go-review.googlesource.com/c/go/+/263577
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Benny Siegert <bsiegert@gmail.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Trust: Benny Siegert <bsiegert@gmail.com>
Implement Access using Faccessat on aix following golang.org/x/sys/unix
CL 262897 and switch cmd/go/internal/modload to use it to implement
hasWritePerm.
Change-Id: I682e44737ac2bac5a203ac1c9ddd277810454426
Reviewed-on: https://go-review.googlesource.com/c/go/+/263540
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
These are the core interfaces for the io/fs design.
See #41190 and https://golang.org/s/draft-iofs-design for details.
DirEntry was left behind in the previous move from os
but is needed for ReadDirFile, so it moves in this commit.
Also apply a couple comment changes suggested in
the review of CL 261540.
For #41190.
Change-Id: I087741545139ed30b9ba5db728a0bad71129500b
Reviewed-on: https://go-review.googlesource.com/c/go/+/243908
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Rob Pike <r@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
There are many reader behaviors that are subtle and
worth testing, and it's nice to have one complete tester
instead of many incomplete ones.
For #41190, which will use this as part of a larger
file system implementation tester.
Change-Id: Ib4cc7fae94b0d9b45dfacadc52baa77ad3761322
Reviewed-on: https://go-review.googlesource.com/c/go/+/243909
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
The old os references are still valid, but update our code
to reflect best practices and get used to the new locations.
Code compiled with the bootstrap toolchain
(cmd/asm, cmd/dist, cmd/compile, debug/elf)
must remain Go 1.4-compatible and is excluded.
For #41190.
Change-Id: I8f9526977867c10a221e2f392f78d7dec073f1bd
Reviewed-on: https://go-review.googlesource.com/c/go/+/243907
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Cgo programs work as well. Still not enabled by default for now.
Enable internal linking tests.
Updates #38485.
Change-Id: I8324a5c263fba221eb4e67d71207ca84fa241e6c
Reviewed-on: https://go-review.googlesource.com/c/go/+/263637
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
This helps the compiler reports the right place where the type declared,
instead of relying on global lineno, which maybe set to wrong value at
the time the error is reported.
Fixes#42058
Change-Id: I06d34aa9b0236d122f4a0d72e66675ded022baac
Reviewed-on: https://go-review.googlesource.com/c/go/+/263597
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
A bunch of new API hasn't been added yet and is cluttering all.bash output.
Change-Id: Ic7f255cce8c162716b9a1144f78b5f9ce6220b33
Reviewed-on: https://go-review.googlesource.com/c/go/+/262878
Trust: Russ Cox <rsc@golang.org>
Trust: Rob Pike <r@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Necessary to move PathError to io/fs.
For #41190.
Change-Id: I05e87675f38a22f0570d4366b751b6169f7a1b13
Reviewed-on: https://go-review.googlesource.com/c/go/+/243900
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
ReadDir provides a portable, efficient way to read a directory
and discover the type of directory entries.
This enables a more efficient file system walk, yet to be added.
See #41467 for the proposal review for the API.
Fixes#41467.
Change-Id: I461a526793ae46df48821aa448b04f1705546739
Reviewed-on: https://go-review.googlesource.com/c/go/+/261540
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Preparation step for types2 package.
Change-Id: I8f9557b1a48ad570ba38aac7b720e639218dc6a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/263623
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
OCALLPART is exported in its original form, which is as an OXDOT.
The body of the method value wrapper created in makepartialcall() was
not being typechecked, and that was causing a problem during escape
analysis, so I added code to typecheck the body.
The go executable got slightly bigger with this change (13598111 ->
13598905), because of extra exported methods with OCALLPART (I
believe), while the text size got slightly smaller (9686964 ->
9686643).
This is mainly part of the work to make sure all function bodies can
be exported (for purposes of generics), but might as well fix the
OCALLPART inlining bug as well.
Fixes#18493
Change-Id: If7aa055ff78ed7a6330c6a1e22f836ec567d04fd
Reviewed-on: https://go-review.googlesource.com/c/go/+/263620
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
finlock may be held across a write barrier, which could then acquire the
mheap lock. Notably, this occurs in the mp.unlockf write in gopark where
finlock is held by the finalizer goroutines and is going to sleep.
Fixes#42062.
Change-Id: Icf76637ae6fc12795436272633dca3d473780875
Reviewed-on: https://go-review.googlesource.com/c/go/+/263678
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
asNode(t.Nod).Name.Param will be nil for builtin types (i.e., the
universal predeclared types and unsafe.Pointer). These types can't be
part of a cycle anyway, so we can just skip them.
Fixes#42075.
Change-Id: Ic7a44de65c6bfd16936545dee25e36de8850acf3
Reviewed-on: https://go-review.googlesource.com/c/go/+/263717
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
This reverts CL 254977.
Reason for revert: introduced test failures on longtest builders.
Change-Id: I75e868245f980189ad85dd4103d9178989e06ecf
Reviewed-on: https://go-review.googlesource.com/c/go/+/263658
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
This extends a change made in https://golang.org/cl/252258 to the go
command (to define an asm macro when GOEXPERIMENT=regabi is in
effect); we need this same macro during the bootstrap build in order
to build the runtime correctly.
In addition, expand the set of packages where the macro is applied to
{runtime, reflect, syscall, runtime/internal/*}, and move the logic
for deciding when something is a "runtime package" out of the
assembler and into cmd/{go,dist}, introducing a new assembler command
line flag instead.
Updates #27539, #40724.
Change-Id: Ifcc7f029f56873584de1e543c55b0d3e54ad6c49
Reviewed-on: https://go-review.googlesource.com/c/go/+/262317
Trust: Than McIntosh <thanm@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The fastest compression mode can pick up a false match for every 2GB
of input data resulting in incorrectly decompressed data.
Since matches are allowed to be up to and including at maxMatchOffset
we must offset the buffer by an additional element to prevent the first
4 bytes to match after an out-of-reach value after shiftOffsets has
been called.
We offset by `maxMatchOffset + 1` so offset 0 in the table will now
fail the `if offset > maxMatchOffset` in all cases.
Fixes#41420
Change-Id: If1fbe01728e132b8a207e3f3f439edd832dcc710
GitHub-Last-Rev: 50fabab0da
GitHub-Pull-Request: golang/go#41477
Reviewed-on: https://go-review.googlesource.com/c/go/+/255879
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Joe Tsai <thebrokentoaster@gmail.com>
Trust: Matthew Dempsky <mdempsky@google.com>
Like we do for applying relocations, for generator symbols, run
the generator function along with symbol writing. This will
probably have better locality and parallelism.
Linking cmd/compile,
Asmb 29.9ms ± 5% 19.1ms ±12% -36.18% (p=0.000 n=10+9)
TotalTime 351ms ± 3% 339ms ± 2% -3.51% (p=0.000 n=11+10)
Change-Id: I9cda6718bf70b3bcf1b7a501a845d6136234d2ee
Reviewed-on: https://go-review.googlesource.com/c/go/+/263640
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Use GOOS=ios.
Run "xcodebuild -showsdks" correctly.
Wrap testDWARF in subtests, as it calls t.Parallel, otherwise
the two calls of testDWARF will cause t.Parallel being called
twice, which panics.
Updates #38485.
Change-Id: I614c8daa99c83cbfd05a4cfa041968d49279f16a
Reviewed-on: https://go-review.googlesource.com/c/go/+/263639
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
ParseMultipartForm has been changed to return an error if maxMemory
parameter + 10MB causes int overflows. This adds a test for the new
behaviour.
For #40430
Change-Id: I4f66ce8a9382940182011d22a84ee52b1d1364cf
Reviewed-on: https://go-review.googlesource.com/c/go/+/254977
Reviewed-by: Damien Neil <dneil@google.com>
Trust: Damien Neil <dneil@google.com>
Trust: Brad Fitzpatrick <bradfitz@golang.org>
Also put Reset in the correct place for the other
benchmarks.
name old time/op new time/op delta
NewWriteSum-8 1.01µs ± 0% 1.01µs ± 1% ~ (p=0.945 n=9+9)
name old speed new speed delta
NewWriteSum-8 31.7MB/s ± 0% 31.6MB/s ± 1% ~ (p=0.948 n=9+9)
name old alloc/op new alloc/op delta
NewWriteSum-8 544B ± 0% 544B ± 0% ~ (all equal)
name old allocs/op new allocs/op delta
NewWriteSum-8 7.00 ± 0% 7.00 ± 0% ~ (all equal)
Fixes#41089
Change-Id: I3dae660adbe4993963130bf3c2636bd53899164b
Reviewed-on: https://go-review.googlesource.com/c/go/+/261960
Trust: Katie Hockman <katie@golang.org>
Trust: Roland Shoemaker <roland@golang.org>
Run-TryBot: Katie Hockman <katie@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>
We don't put Go static symbols in the symbol table, as they are
always compiler-generated (there is no way to define a static
symbol in user code in Go). We retain static symbols in assembly
code, as it may be user-defined. Also retain static symbols in C.
Change-Id: Ie0425bb4df33f183857b1fd5ba4b2bdfdc497571
Reviewed-on: https://go-review.googlesource.com/c/go/+/263259
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
This reverts CL 263097.
Reason for revert: broke the noopt builder.
Change-Id: Ie36d2c3ed9449b4425732072db624c8e18f965f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/263537
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
This brings in CL 262197, which enables handling of ABI selector
syntax in the asmdecl checker.
Updates #27539, #40724.
Change-Id: I088f5eeacb3588ed49c4aa2277641049bf5b9083
Reviewed-on: https://go-review.googlesource.com/c/go/+/262318
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Than McIntosh <thanm@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Function symbols defined and referenced by assembly source currently
always default to ABI0; this patch adds preliminary support for
accepting an explicit ABI selector clause for func defs/refs. This
functionality is currently only enabled when compiling runtime-related
packages (runtime, syscall, reflect). Examples:
TEXT ·DefinedAbi0Symbol<ABI0>(SB),NOSPLIT,$0
RET
TEXT ·DefinedAbi1Symbol<ABIInternal>(SB),NOSPLIT,$0
CALL ·AbiZerolSym<ABI0>(SB)
...
JMP ·AbiInternalSym<ABIInternal>(SB)
RET
Also included is a small change to the code in the compiler that reads
the symabis file emitted by the assembler.
New behavior is currently gated under GOEXPERIMENT=regabi.
Updates #27539, #40724.
Change-Id: Ia22221fe26df0fa002191cfb13bdfaaa38d7df38
Reviewed-on: https://go-review.googlesource.com/c/go/+/260477
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Trust: Than McIntosh <thanm@google.com>
On OpenBSD/octeon `uname -m` returns 'octeon' and we need `uname -p` to determine
the processor type (mips64).
Update #40995
Change-Id: I37c53ca2c372ab958fff17917d82d41f4b0a0393
Reviewed-on: https://go-review.googlesource.com/c/go/+/250583
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
@jstarks suggested that recent versions of Windows provide access to high resolution timers. See
https://github.com/golang/go/issues/8687#issuecomment-656259353
for details.
I tried to run this C program on my Windows 10 computer
```
#include <stdio.h>
#include <Windows.h>
#pragma comment(lib, "Winmm.lib")
// Apparently this is already defined when I use msvc cl.
//#define CREATE_WAITABLE_TIMER_HIGH_RESOLUTION = 0x00000002;
int usleep(HANDLE timer, LONGLONG d) {
LARGE_INTEGER liDueTime;
DWORD ret;
LARGE_INTEGER StartingTime, EndingTime, ElapsedMicroseconds;
LARGE_INTEGER Frequency;
QueryPerformanceFrequency(&Frequency);
QueryPerformanceCounter(&StartingTime);
liDueTime.QuadPart = d;
liDueTime.QuadPart = liDueTime.QuadPart * 10; // us into 100 of ns units
liDueTime.QuadPart = -liDueTime.QuadPart; // negative for relative dure time
if (!SetWaitableTimer(timer, &liDueTime, 0, NULL, NULL, 0)) {
printf("SetWaitableTimer failed: errno=%d\n", GetLastError());
return 1;
}
ret = WaitForSingleObject(timer, INFINITE);
if (ret != WAIT_OBJECT_0) {
printf("WaitForSingleObject failed: ret=%d errno=%d\n", ret, GetLastError());
return 1;
}
QueryPerformanceCounter(&EndingTime);
ElapsedMicroseconds.QuadPart = EndingTime.QuadPart - StartingTime.QuadPart;
ElapsedMicroseconds.QuadPart *= 1000000;
ElapsedMicroseconds.QuadPart /= Frequency.QuadPart;
printf("delay is %lld us - slept for %lld us\n", d, ElapsedMicroseconds.QuadPart);
return 0;
}
int testTimer(DWORD createFlag)
{
HANDLE timer;
timer = CreateWaitableTimerEx(NULL, NULL, createFlag, TIMER_ALL_ACCESS);
if (timer == NULL) {
printf("CreateWaitableTimerEx failed: errno=%d\n", GetLastError());
return 1;
}
usleep(timer, 1000LL);
usleep(timer, 100LL);
usleep(timer, 10LL);
usleep(timer, 1LL);
CloseHandle(timer);
return 0;
}
int main()
{
printf("\n1. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is off\n");
testTimer(0);
printf("\n2. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is off\n");
testTimer(CREATE_WAITABLE_TIMER_HIGH_RESOLUTION);
timeBeginPeriod(1);
printf("\n3. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is on\n");
testTimer(0);
printf("\n4. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is on\n");
testTimer(CREATE_WAITABLE_TIMER_HIGH_RESOLUTION);
}
```
and I see this output
```
1. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is off
delay is 1000 us - slept for 4045 us
delay is 100 us - slept for 3915 us
delay is 10 us - slept for 3291 us
delay is 1 us - slept for 2234 us
2. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is off
delay is 1000 us - slept for 1076 us
delay is 100 us - slept for 569 us
delay is 10 us - slept for 585 us
delay is 1 us - slept for 17 us
3. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is off - timeBeginPeriod is on
delay is 1000 us - slept for 742 us
delay is 100 us - slept for 893 us
delay is 10 us - slept for 414 us
delay is 1 us - slept for 920 us
4. CREATE_WAITABLE_TIMER_HIGH_RESOLUTION is on - timeBeginPeriod is on
delay is 1000 us - slept for 1466 us
delay is 100 us - slept for 559 us
delay is 10 us - slept for 535 us
delay is 1 us - slept for 5 us
```
That shows, that indeed using CREATE_WAITABLE_TIMER_HIGH_RESOLUTION
will provide sleeps as low as about 500 microseconds, while our
current approach provides about 1 millisecond sleep.
New approach also does not require for timeBeginPeriod to be on,
so this change solves long standing problem with go programs draining
laptop battery, because it calls timeBeginPeriod.
This change will only run on systems where
CREATE_WAITABLE_TIMER_HIGH_RESOLUTION flag is available. If not
available, the runtime will fallback to original code that uses
timeBeginPeriod.
This is how this change affects benchmark reported in issue #14790
name old time/op new time/op delta
ChanToSyscallPing 1.05ms ± 2% 0.68ms ±11% -35.43% (p=0.000 n=10+10)
The benchmark was run with GOMAXPROCS set to 1.
Fixes#8687
Updates #14790
Change-Id: I5b97ba58289c088c17c05292e12e45285c467eae
Reviewed-on: https://go-review.googlesource.com/c/go/+/248699
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Austin Clements <austin@google.com>
