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authorLinus Torvalds <torvalds@linux-foundation.org>2008-11-08 10:24:28 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2008-11-08 10:24:28 -0800
commita622cf69b806bbb1887913c04e01d0c25b892876 (patch)
tree08c2da8eea9ab32957735672514c603e96a402be /arch
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
Diffstat (limited to 'arch')
-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 46be2fa7ac2..c2a812ebde8 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 38ae163cc91..9cd83a8e40d 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 2ef80e30192..424093b157d 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