From: Anton Blanchard <an...@samba.org>
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 <an...@samba.org>
---
arch/powerpc/include/asm/atomic.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/include/asm/atomic.h
b/arch/powerpc/include/asm/atomic.h
index f08d567..2b90335 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"
--
2.7.4
