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| author | Ingo Molnar <mingo@elte.hu> | 2009-05-17 19:37:25 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-18 09:37:09 +0200 |
| commit | b68f1d2e7aa21029d73c7d453a8046e95d351740 (patch) | |
| tree | 2fa9e94f340e84e037bce4d3e3ffd5a6f88a9039 /arch | |
| parent | c0daaf3f1f672defa3a45ca449b76d0e86c55892 (diff) | |
| download | op-kernel-dev-b68f1d2e7aa21029d73c7d453a8046e95d351740.zip op-kernel-dev-b68f1d2e7aa21029d73c7d453a8046e95d351740.tar.gz | |
perf_counter, x86: speed up the scheduling fast-path
We have to set up the LVT entry only at counter init time, not at
every switch-in time.
There's friction between NMI and non-NMI use here - we'll probably
remove the per counter configurability of it - but until then, dont
slow down things ...
[ Impact: micro-optimization ]
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 5bfd30a..c109819 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -285,6 +285,7 @@ static int __hw_perf_counter_init(struct perf_counter *counter) return -EACCES; hwc->nmi = 1; } + perf_counters_lapic_init(hwc->nmi); if (!hwc->irq_period) hwc->irq_period = x86_pmu.max_period; @@ -603,8 +604,6 @@ try_generic: hwc->counter_base = x86_pmu.perfctr; } - perf_counters_lapic_init(hwc->nmi); - x86_pmu.disable(hwc, idx); cpuc->counters[idx] = counter; @@ -1054,7 +1053,7 @@ void __init init_hw_perf_counters(void) pr_info("... counter mask: %016Lx\n", perf_counter_mask); - perf_counters_lapic_init(0); + perf_counters_lapic_init(1); register_die_notifier(&perf_counter_nmi_notifier); } |
