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authorLinus Torvalds <torvalds@linux-foundation.org>2008-11-08 13:24:28 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2008-11-08 13:24:28 -0500
commita622cf69b806bbb1887913c04e01d0c25b892876 (patch)
tree08c2da8eea9ab32957735672514c603e96a402be
parentaf3e48ffce029a191f1bc4b8550e8571303233d5 (diff)
parent7cbaef9c83e58bbd4bdd534b09052b6c5ec457d5 (diff)
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
-rw-r--r--arch/x86/include/asm/msr.h2
-rw-r--r--arch/x86/include/asm/tsc.h8
-rw-r--r--arch/x86/kernel/tsc.c2
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)
108{ 108{
109 DECLARE_ARGS(val, low, high); 109 DECLARE_ARGS(val, low, high);
110 110
111 rdtsc_barrier();
112 asm volatile("rdtsc" : EAX_EDX_RET(val, low, high)); 111 asm volatile("rdtsc" : EAX_EDX_RET(val, low, high));
113 rdtsc_barrier();
114 112
115 return EAX_EDX_VAL(val, low, high); 113 return EAX_EDX_VAL(val, low, high);
116} 114}
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)
34 34
35static __always_inline cycles_t vget_cycles(void) 35static __always_inline cycles_t vget_cycles(void)
36{ 36{
37 cycles_t cycles;
38
37 /* 39 /*
38 * We only do VDSOs on TSC capable CPUs, so this shouldnt 40 * We only do VDSOs on TSC capable CPUs, so this shouldnt
39 * access boot_cpu_data (which is not VDSO-safe): 41 * access boot_cpu_data (which is not VDSO-safe):
@@ -42,7 +44,11 @@ static __always_inline cycles_t vget_cycles(void)
42 if (!cpu_has_tsc) 44 if (!cpu_has_tsc)
43 return 0; 45 return 0;
44#endif 46#endif
45 return (cycles_t)__native_read_tsc(); 47 rdtsc_barrier();
48 cycles = (cycles_t)__native_read_tsc();
49 rdtsc_barrier();
50
51 return cycles;
46} 52}
47 53
48extern void tsc_init(void); 54extern 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)
55 rdtscll(this_offset); 55 rdtscll(this_offset);
56 56
57 /* return the value in ns */ 57 /* return the value in ns */
58 return cycles_2_ns(this_offset); 58 return __cycles_2_ns(this_offset);
59} 59}
60 60
61/* We need to define a real function for sched_clock, to override the 61/* We need to define a real function for sched_clock, to override the