This CL adds the ability to enable the cpu feature FEATURE by specifying
FEATURE=on in GODEBUGCPU. Syntax support to enable cpu features is useful
in combination with a preceeding all=off to disable all but some specific
cpu features. Example:
GODEBUGCPU=all=off,sse3=on
This CL implements printing of warnings for invalid GODEBUGCPU settings:
- requests enabling features that are not supported with the current CPU
- specifying values different than 'on' or 'off' for a feature
- settings for unkown cpu feature names
Updates #27218
Change-Id: Ic13e5c4c35426a390c50eaa4bd2a408ef2ee21be
Reviewed-on: https://go-review.googlesource.com/c/141800
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The new constant CacheLinePadSize can be used to compute best effort
alignment of structs to cache lines.
e.g. the runtime can use this in the locktab definition:
var locktab [57]struct {
l spinlock
pad [cpu.CacheLinePadSize - unsafe.Sizeof(spinlock{})]byte
}
Change-Id: I86f6fbfc5ee7436f742776a7d4a99a1d54ffccc8
Reviewed-on: https://go-review.googlesource.com/131237
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The runtime package already imports the internal/cpu package, so there
is no reason for it to use go:linkname comments to refer to
internal/cpu functions and variables. Since internal/cpu is internal,
we can just export those names. Removing the obscurity of go:linkname
outweighs the minor additional complexity added to the internal/cpu API.
Change-Id: Id89951b7f3fc67cd9bce67ac6d01d44a647a10ad
Reviewed-on: https://go-review.googlesource.com/128755
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
The parentheses are not required for the definitions and it brings
the declaration style in line with other architectures feature bits
defined in internal/cpu.
Change-Id: I86cc3812c1488216779e0d1f0e7481687502e592
Reviewed-on: https://go-review.googlesource.com/126775
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Needs the go compiler to be build with GOEXPERIMENT=debugcpu to be active.
The GODEBUGCPU environment variable can be used to disable usage of
specific processor features in the Go standard library.
This is useful for testing and benchmarking different code paths that
are guarded by internal/cpu variable checks.
Use of processor features can not be enabled through GODEBUGCPU.
To disable usage of AVX and SSE41 cpu features on GOARCH amd64 use:
GODEBUGCPU=avx=0,sse41=0
The special "all" option can be used to disable all options:
GODEBUGCPU=all=0
Updates #12805
Updates #15403
Change-Id: I699c2e6f74d98472b6fb4b1e5ffbf29b15697aab
Reviewed-on: https://go-review.googlesource.com/91737
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Go runtime currently only populates hwcap for ppc64 and arm64.
While the interpretation of hwcap is platform specific the hwcap
information is generally available on linux.
Changing the runtime variable name to cpu_hwcap for cpu.hwcap makes it
consistent with the general naming of runtime variables that are linked
to other packages.
Change-Id: I1e1f932a73ed624a219b9298faafbb6355e47ada
Reviewed-on: https://go-review.googlesource.com/94757
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The file name suffix arm64 already limits the file to be build only on arm64.
Change-Id: I33db713041b6dec9eb00889bac3b54c727e90743
Reviewed-on: https://go-review.googlesource.com/108986
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
runtime.alginit needs runtime/support_{aes,ssse3,sse41} feature flag
to init aeshash function but internal/cpu.init not be called yet.
This CL will call internal/cpu.initialize before runtime.alginit, so
that we can move all cpu features related code to internal/cpu.
Change-Id: I00b8e403ace3553f8c707563d95f27dade0bc853
Reviewed-on: https://go-review.googlesource.com/104636
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This makes the constant names less verbose and aligns them more
with the Linux kernel which uses HWCAP_XXX for the constant names.
Change-Id: Ia7d079b59b57978adc045945951eaa1d99b41fac
Reviewed-on: https://go-review.googlesource.com/91738
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
change hash/crc32 package to use cpu package instead of using
runtime internal variables to check crc32 instruction
Change-Id: I8f88d2351bde8ed4e256f9adf822a08b9a00f532
Reviewed-on: https://go-review.googlesource.com/76490
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
I submitted two CLs which broke the build. Add temporary placeholder
with false bools to fix the build and restore old behavior.
Updates golang/go#22718 (details of why it broke)
Change-Id: I1f30624e14f631a95f4eff5aae462f1091f723a2
Reviewed-on: https://go-review.googlesource.com/77590
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
According to http://infocenter.arm.com:
* ARM Cortex-A53 (Raspberry Pi 3, Pine A64)
* ARM Cortex-A57 (Opteron A1100, Tegra X1)
* ARM Cortex-A72
all have a cache line size of 64 bytes.
Change-Id: I4b333e930792fb1a221b3ca6f395bfa1b7762afa
Reviewed-on: https://go-review.googlesource.com/43250
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Implements detection of x86 cpu features that
are used in the go standard library.
Changes all standard library packages to use the new cpu package
instead of using runtime internal variables to check x86 cpu features.
Updates: #15403
Change-Id: I2999a10cb4d9ec4863ffbed72f4e021a1dbc4bb9
Reviewed-on: https://go-review.googlesource.com/41476
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Martin Möhrmann
Ian Lance Taylor
Meng Zhuo
Fangming.Fang
Brad Fitzpatrick