diff options
| author | Yong Zhang <yong.zhang at windriver.com> | 2015-01-29 12:56:18 -0600 |
|---|---|---|
| committer | Anders Roxell <anders.roxell@linaro.org> | 2015-06-26 22:31:40 +0200 |
| commit | f864ba5e069f487d106b82834c06d1fc9e693b16 (patch) | |
| tree | 3584c3737e105fdb3c021883a9221c798d81ed63 /arch/arm | |
| parent | 32dec560862b8dafbdcf728541050abf238cb236 (diff) | |
ARM: cmpxchg: define __HAVE_ARCH_CMPXCHG for armv6 and later
Both pi_stress and sigwaittest in rt-test show performance gain with
__HAVE_ARCH_CMPXCHG. Testing result on coretile_express_a9x4:
pi_stress -p 99 --duration=300 (on linux-3.4-rc5; bigger is better)
vanilla: Total inversion performed: 5493381
patched: Total inversion performed: 5621746
sigwaittest -p 99 -l 100000 (on linux-3.4-rc5-rt6; less is better)
3.4-rc5-rt6: Min 24, Cur 27, Avg 30, Max 98
patched: Min 19, Cur 21, Avg 23, Max 96
Signed-off-by: Yong Zhang <yong.zhang0 at gmail.com>
Cc: Russell King <rmk+kernel at arm.linux.org.uk>
Cc: Nicolas Pitre <nico at linaro.org>
Cc: Will Deacon <will.deacon at arm.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: linux-arm-kernel at lists.infradead.org
Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/include/asm/cmpxchg.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm/include/asm/cmpxchg.h b/arch/arm/include/asm/cmpxchg.h index df2fbba7efc8..30b1a4010b89 100644 --- a/arch/arm/include/asm/cmpxchg.h +++ b/arch/arm/include/asm/cmpxchg.h @@ -127,6 +127,8 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size #else /* min ARCH >= ARMv6 */ +#define __HAVE_ARCH_CMPXCHG 1 + extern void __bad_cmpxchg(volatile void *ptr, int size); /* |