diff options
| author | Anton Blanchard <anton@samba.org> | 2016-10-03 17:03:03 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-10-04 16:13:13 +1100 |
| commit | 61e98ebff3ba3d3b17e999dc483c2680480ed715 (patch) | |
| tree | 3413b146a703edb4e7a5cbf963ce57a639ef791b /arch/powerpc/include/asm/atomic.h | |
| parent | bb85fb5803270c52863b983596c2a038facaf4b3 (diff) | |
| download | lwn-61e98ebff3ba3d3b17e999dc483c2680480ed715.tar.gz lwn-61e98ebff3ba3d3b17e999dc483c2680480ed715.zip | |
powerpc: Remove static branch prediction in atomic{, 64}_add_unless
I see quite a lot of static branch mispredictions on a simple
web serving workload. The issue is in __atomic_add_unless(), called
from _atomic_dec_and_lock(). There is no obvious common case, so it
is better to let the hardware predict the branch.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/atomic.h')
| -rw-r--r-- | arch/powerpc/include/asm/atomic.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h index f08d567e0ca4..2b90335194a7 100644 --- a/arch/powerpc/include/asm/atomic.h +++ b/arch/powerpc/include/asm/atomic.h @@ -233,7 +233,7 @@ static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) PPC_ATOMIC_ENTRY_BARRIER "1: lwarx %0,0,%1 # __atomic_add_unless\n\ cmpw 0,%0,%3 \n\ - beq- 2f \n\ + beq 2f \n\ add %0,%2,%0 \n" PPC405_ERR77(0,%2) " stwcx. %0,0,%1 \n\ @@ -539,7 +539,7 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) PPC_ATOMIC_ENTRY_BARRIER "1: ldarx %0,0,%1 # __atomic_add_unless\n\ cmpd 0,%0,%3 \n\ - beq- 2f \n\ + beq 2f \n\ add %0,%2,%0 \n" " stdcx. %0,0,%1 \n\ bne- 1b \n" |