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author | Peter Zijlstra <peterz@infradead.org> | 2013-11-28 19:31:23 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2014-01-13 15:13:11 +0100 |
commit | ef08f0fff87630d4f67ceb09514d8b444df833f8 (patch) | |
tree | be33021d329f9f2780ed8eac7cb8acb19a56a1b4 /kernel | |
parent | 20d1c86a57762f0a33a78988e3fc8818316badd4 (diff) | |
download | linux-stable-ef08f0fff87630d4f67ceb09514d8b444df833f8.tar.gz linux-stable-ef08f0fff87630d4f67ceb09514d8b444df833f8.tar.bz2 linux-stable-ef08f0fff87630d4f67ceb09514d8b444df833f8.zip |
sched/clock: Remove local_irq_disable() from the clocks
Now that x86 no longer requires IRQs disabled for sched_clock() and
ia64 never had this requirement (it doesn't seem to do cpufreq at
all), we can remove the requirement of disabling IRQs.
MAINLINE PRE POST
sched_clock_stable: 1 1 1
(cold) sched_clock: 329841 257223 221876
(cold) local_clock: 301773 309889 234692
(warm) sched_clock: 38375 25280 25602
(warm) local_clock: 100371 85268 33265
(warm) rdtsc: 27340 24247 24214
sched_clock_stable: 0 0 0
(cold) sched_clock: 382634 301224 235941
(cold) local_clock: 396890 399870 297017
(warm) sched_clock: 38194 25630 25233
(warm) local_clock: 143452 129629 71234
(warm) rdtsc: 27345 24307 24245
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-36e5kohiasnr106d077mgubp@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/sched/clock.c | 34 |
1 files changed, 6 insertions, 28 deletions
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index c3ae1446461c..59371549ddf0 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -26,9 +26,10 @@ * at 0 on boot (but people really shouldn't rely on that). * * cpu_clock(i) -- can be used from any context, including NMI. - * sched_clock_cpu(i) -- must be used with local IRQs disabled (implied by NMI) * local_clock() -- is cpu_clock() on the current cpu. * + * sched_clock_cpu(i) + * * How: * * The implementation either uses sched_clock() when @@ -50,15 +51,6 @@ * Furthermore, explicit sleep and wakeup hooks allow us to account for time * that is otherwise invisible (TSC gets stopped). * - * - * Notes: - * - * The !IRQ-safetly of sched_clock() and sched_clock_cpu() comes from things - * like cpufreq interrupts that can change the base clock (TSC) multiplier - * and cause funny jumps in time -- although the filtering provided by - * sched_clock_cpu() should mitigate serious artifacts we cannot rely on it - * in general since for !CONFIG_HAVE_UNSTABLE_SCHED_CLOCK we fully rely on - * sched_clock(). */ #include <linux/spinlock.h> #include <linux/hardirq.h> @@ -242,20 +234,20 @@ u64 sched_clock_cpu(int cpu) struct sched_clock_data *scd; u64 clock; - WARN_ON_ONCE(!irqs_disabled()); - if (sched_clock_stable) return sched_clock(); if (unlikely(!sched_clock_running)) return 0ull; + preempt_disable(); scd = cpu_sdc(cpu); if (cpu != smp_processor_id()) clock = sched_clock_remote(scd); else clock = sched_clock_local(scd); + preempt_enable(); return clock; } @@ -316,14 +308,7 @@ EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); */ u64 cpu_clock(int cpu) { - u64 clock; - unsigned long flags; - - local_irq_save(flags); - clock = sched_clock_cpu(cpu); - local_irq_restore(flags); - - return clock; + return sched_clock_cpu(cpu); } /* @@ -335,14 +320,7 @@ u64 cpu_clock(int cpu) */ u64 local_clock(void) { - u64 clock; - unsigned long flags; - - local_irq_save(flags); - clock = sched_clock_cpu(smp_processor_id()); - local_irq_restore(flags); - - return clock; + return sched_clock_cpu(raw_smp_processor_id()); } #else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */ |