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| author | Cherry Zhang <cherryyz@google.com> | 2018-02-14 14:51:39 -0500 |
|---|---|---|
| committer | Cherry Zhang <cherryyz@google.com> | 2018-05-03 21:35:39 +0000 |
| commit | 150b728675c64addd24d79ad3bb68fec4c137940 (patch) | |
| tree | a17449aedd1204ab7c05d3cef5a2bf2e9a83f814 /src/runtime/internal/atomic/sys_linux_arm.s | |
| parent | 1b6fec862cbe890ef0abea99827a587ffbe2e0f1 (diff) | |
| download | go-150b728675c64addd24d79ad3bb68fec4c137940.tar.xz | |
runtime: use native CAS and memory barrier on ARMv7
This gets us around the kernel helpers on ARMv7.
It is slightly faster than using the kernel helper.
name old time/op new time/op delta
AtomicLoad-4 72.5ns ± 0% 69.5ns ± 0% -4.08% (p=0.000 n=9+9)
AtomicStore-4 57.6ns ± 1% 54.4ns ± 0% -5.58% (p=0.000 n=10+9)
[Geo mean] 64.6ns 61.5ns -4.83%
If performance is really critical, we can even do compiler intrinsics
on GOARM=7.
Fixes #23792.
Change-Id: I36497d880890b26bdf01e048b542bd5fd7b17d23
Reviewed-on: https://go-review.googlesource.com/94076
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/runtime/internal/atomic/sys_linux_arm.s')
| -rw-r--r-- | src/runtime/internal/atomic/sys_linux_arm.s | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/src/runtime/internal/atomic/sys_linux_arm.s b/src/runtime/internal/atomic/sys_linux_arm.s index 60f28e7216..7e234d8f26 100644 --- a/src/runtime/internal/atomic/sys_linux_arm.s +++ b/src/runtime/internal/atomic/sys_linux_arm.s @@ -24,7 +24,14 @@ TEXT cas<>(SB),NOSPLIT,$0 MOVW $0xffff0fc0, R15 // R15 is hardware PC. -TEXT runtime∕internal∕atomic·Cas(SB),NOSPLIT,$0 +TEXT runtime∕internal∕atomic·Cas(SB),NOSPLIT|NOFRAME,$0 + MOVB runtime·goarm(SB), R11 + CMP $7, R11 + BLT 2(PC) + JMP ·armcas(SB) + JMP ·kernelcas<>(SB) + +TEXT runtime∕internal∕atomic·kernelcas<>(SB),NOSPLIT,$0 MOVW ptr+0(FP), R2 // trigger potential paging fault here, // because we don't know how to traceback through __kuser_cmpxchg |