tree 7f9df537c5092f6a17210cd4793e85348c632b62
parent 64077c9b5642ac67ce07bc05738eb432a9029f93
author Polina Osadcha <polliosa@google.com> 1594277257 +0300
committer Martin Möhrmann <moehrmann@google.com> 1596610543 +0000

cpu: add GODEBUG options to disable use of instruction set extensions

The GODEBUG environment variable can be used to disable usage of
specific processor features of Go programs that use the sys/cpu package.
This is useful for testing and benchmarking different code paths that
are guarded by sys/cpu variable checks.

Use of processor features can not be enabled through GODEBUG.

To disable usage of AVX and SSE41 cpu features on GOARCH amd64 use:
GODEBUG=cpu.avx=off,cpu.sse41=off

The special "all" option can be used to disable all options:
GODEBUG=all=off

This aligns the support of GODEBUG for sys/cpu with existing support
for GODEBUG in the Go standard library package internal/cpu.

Fixes golang/go#33963

Change-Id: I618b71af397bf06c57a49b2a300d032a16d05664
Reviewed-on: https://go-review.googlesource.com/c/sys/+/245237
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>