Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: optimize sched_clock() a bit
  sched: improve sched_clock() performance

3 files changed, 8 insertions, 4 deletions

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 46be2fa7ac26..c2a812ebde89 100644
--- a/arch/x86/include/asm/msr.h
+++ b/arch/x86/include/asm/msr.h
@@ -108,9 +108,7 @@ static __always_inline unsigned long long __native_read_tsc(void)
 {
         DECLARE_ARGS(val, low, high);
 
-        rdtsc_barrier();
         asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
-        rdtsc_barrier();
 
         return EAX_EDX_VAL(val, low, high);
 }
diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h
index 38ae163cc91b..9cd83a8e40d5 100644
--- 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);
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 2ef80e301925..424093b157d3 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -55,7 +55,7 @@ u64 native_sched_clock(void)
         rdtscll(this_offset);
 
         /* return the value in ns */
-        return cycles_2_ns(this_offset);
+        return __cycles_2_ns(this_offset);
 }
 
 /* We need to define a real function for sched_clock, to override the