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>
diff --git a/cpu/cpu_aix.go b/cpu/cpu_aix.go
index da29896..464a209 100644
--- a/cpu/cpu_aix.go
+++ b/cpu/cpu_aix.go
@@ -6,8 +6,6 @@
package cpu
-const cacheLineSize = 128
-
const (
// getsystemcfg constants
_SC_IMPL = 2
@@ -15,7 +13,7 @@
_IMPL_POWER9 = 0x20000
)
-func init() {
+func archInit() {
impl := getsystemcfg(_SC_IMPL)
if impl&_IMPL_POWER8 != 0 {
PPC64.IsPOWER8 = true
