diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-06-05 18:01:29 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-05 18:07:48 +0200 |
| commit | 6a24ed6c6082ec65d19331a4bfa30c0512a1a822 (patch) | |
| tree | 0d8beed316cf34cd8e986eb2f9b230a29caa6c88 /kernel | |
| parent | perf_counter: Add PERF_SAMPLE_PERIOD (diff) | |
| download | linux-6a24ed6c6082ec65d19331a4bfa30c0512a1a822.tar.xz linux-6a24ed6c6082ec65d19331a4bfa30c0512a1a822.zip | |
perf_counter: Fix frequency adjustment for < HZ
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/perf_counter.c | 32 |
1 files changed, 25 insertions, 7 deletions
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index f8390668c391..47c92fb927f2 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1187,8 +1187,9 @@ static void perf_log_period(struct perf_counter *counter, u64 period); static void perf_adjust_freq(struct perf_counter_context *ctx) { struct perf_counter *counter; + struct hw_perf_counter *hwc; u64 interrupts, sample_period; - u64 events, period; + u64 events, period, freq; s64 delta; spin_lock(&ctx->lock); @@ -1196,8 +1197,10 @@ static void perf_adjust_freq(struct perf_counter_context *ctx) if (counter->state != PERF_COUNTER_STATE_ACTIVE) continue; - interrupts = counter->hw.interrupts; - counter->hw.interrupts = 0; + hwc = &counter->hw; + + interrupts = hwc->interrupts; + hwc->interrupts = 0; if (interrupts == MAX_INTERRUPTS) { perf_log_throttle(counter, 1); @@ -1208,20 +1211,35 @@ static void perf_adjust_freq(struct perf_counter_context *ctx) if (!counter->attr.freq || !counter->attr.sample_freq) continue; - events = HZ * interrupts * counter->hw.sample_period; + if (counter->attr.sample_freq < HZ) { + freq = counter->attr.sample_freq; + + hwc->freq_count += freq; + hwc->freq_interrupts += interrupts; + + if (hwc->freq_count < HZ) + continue; + + interrupts = hwc->freq_interrupts; + hwc->freq_interrupts = 0; + hwc->freq_count -= HZ; + } else + freq = HZ; + + events = freq * interrupts * hwc->sample_period; period = div64_u64(events, counter->attr.sample_freq); - delta = (s64)(1 + period - counter->hw.sample_period); + delta = (s64)(1 + period - hwc->sample_period); delta >>= 1; - sample_period = counter->hw.sample_period + delta; + sample_period = hwc->sample_period + delta; if (!sample_period) sample_period = 1; perf_log_period(counter, sample_period); - counter->hw.sample_period = sample_period; + hwc->sample_period = sample_period; } spin_unlock(&ctx->lock); } |