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| author | Yong Zhang <yong.zhang at windriver.com> | 2015-01-29 12:56:18 -0600 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2016-06-24 16:32:55 -0400 |
| commit | 33c0cba3cd55e243dcd8842b4ba6e726e826bfa6 (patch) | |
| tree | 9a6da3be3b7ed9f327bcf74b3b6e04a91cef8c19 | |
| parent | 1fdf0887165f7f71e1062bdd93512f8e0b426d56 (diff) | |
| download | linux-rt-33c0cba3cd55e243dcd8842b4ba6e726e826bfa6.tar.gz | |
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>
| -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 d41d7cbf0ada..249dfc34a36f 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); /* |