From e736ad548db152776de61d7a26805cfae77ce5ce Mon Sep 17 00:00:00 2001 From: "Pallipadi, Venkatesh" Date: Fri, 6 Feb 2009 16:52:05 -0800 Subject: x86: add clflush before monitor for Intel 7400 series For Intel 7400 series CPUs, the recommendation is to use a clflush on the monitored address just before monitor and mwait pair [1]. This clflush makes sure that there are no false wakeups from mwait when the monitored address was recently written to. [1] "MONITOR/MWAIT Recommendations for Intel Xeon Processor 7400 series" section in specification update document of 7400 series http://download.intel.com/design/xeon/specupdt/32033601.pdf Signed-off-by: Venkatesh Pallipadi Signed-off-by: Ingo Molnar --- arch/x86/include/asm/cpufeature.h | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/include/asm/cpufeature.h') diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index ea408dc..7301e60 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -93,6 +93,7 @@ #define X86_FEATURE_XTOPOLOGY (3*32+22) /* cpu topology enum extensions */ #define X86_FEATURE_TSC_RELIABLE (3*32+23) /* TSC is known to be reliable */ #define X86_FEATURE_NONSTOP_TSC (3*32+24) /* TSC does not stop in C states */ +#define X86_FEATURE_CLFLUSH_MONITOR (3*32+25) /* "" clflush reqd with monitor */ /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */ #define X86_FEATURE_XMM3 (4*32+ 0) /* "pni" SSE-3 */ -- cgit v1.1