[git pull] scheduler updates

From: Ingo Molnar
Date: Sat Nov 08 2008 - 12:02:48 EST


Linus,

Please pull the latest scheduler updates git tree from:

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

Thanks,

Ingo

------------------>
Ingo Molnar (2):
sched: improve sched_clock() performance
sched: optimize sched_clock() a bit


arch/x86/include/asm/msr.h | 2 --
arch/x86/include/asm/tsc.h | 8 +++++++-
arch/x86/kernel/tsc.c | 2 +-
3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h
index 46be2fa..c2a812e 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 38ae163..9cd83a8 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 2ef80e3..424093b 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/