sched: improve sched_clock() performance

[linux-2.6-omap-h63xx.git] / arch / x86 / include / asm / tsc.h

diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 38ae163cc91b00bf029d5ed5e29cd8ba96bd461b..9cd83a8e40d59a3dae2978e23887d81311370ae3 100644 (file)
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -34,6 +34,8 @@ static inline cycles_t get_cycles(void)
 
 static __always_inline cycles_t vget_cycles(void)
 {
+       cycles_t cycles;
+
        /*
         * We only do VDSOs on TSC capable CPUs, so this shouldnt
         * access boot_cpu_data (which is not VDSO-safe):
@@ -42,7 +44,11 @@ static __always_inline cycles_t vget_cycles(void)
        if (!cpu_has_tsc)
                return 0;
 #endif
-       return (cycles_t)__native_read_tsc();
+       rdtsc_barrier();
+       cycles = (cycles_t)__native_read_tsc();
+       rdtsc_barrier();
+
+       return cycles;
 }
 
 extern void tsc_init(void);