diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2013-11-28 19:38:42 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-01-13 15:13:13 +0100 |
| commit | 35af99e646c7f7ea46dc2977601e9e71a51dadd5 (patch) | |
| tree | d999820d233844278549cd826c4bfd6c7aa1ecc8 /arch/x86/kernel/cpu | |
| parent | ef08f0fff87630d4f67ceb09514d8b444df833f8 (diff) | |
sched/clock, x86: Use a static_key for sched_clock_stable
In order to avoid the runtime condition and variable load turn
sched_clock_stable into a static_key.
Also provide a shorter implementation of local_clock() and
cpu_clock(int) when sched_clock_stable==1.
MAINLINE PRE POST
sched_clock_stable: 1 1 1
(cold) sched_clock: 329841 221876 215295
(cold) local_clock: 301773 234692 220773
(warm) sched_clock: 38375 25602 25659
(warm) local_clock: 100371 33265 27242
(warm) rdtsc: 27340 24214 24208
sched_clock_stable: 0 0 0
(cold) sched_clock: 382634 235941 237019
(cold) local_clock: 396890 297017 294819
(warm) sched_clock: 38194 25233 25609
(warm) local_clock: 143452 71234 71232
(warm) rdtsc: 27345 24245 24243
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-eummbdechzz37mwmpags1gjr@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/cpu')
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/intel.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event.c | 2 |
3 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index bca023bdd6b2..8bc79cddd9a2 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -487,7 +487,7 @@ static void early_init_amd(struct cpuinfo_x86 *c) set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC); if (!check_tsc_unstable()) - sched_clock_stable = 1; + set_sched_clock_stable(); } #ifdef CONFIG_X86_64 diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index ea04b342c026..1a439c047ff3 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -93,7 +93,7 @@ static void early_init_intel(struct cpuinfo_x86 *c) set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC); if (!check_tsc_unstable()) - sched_clock_stable = 1; + set_sched_clock_stable(); } /* Penwell and Cloverview have the TSC which doesn't sleep on S3 */ diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 9f97bd03f74f..b88645191fe5 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1890,7 +1890,7 @@ void arch_perf_update_userpage(struct perf_event_mmap_page *userpg, u64 now) userpg->cap_user_rdpmc = x86_pmu.attr_rdpmc; userpg->pmc_width = x86_pmu.cntval_bits; - if (!sched_clock_stable) + if (!sched_clock_stable()) return; data = cyc2ns_read_begin(); |