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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-06-10 23:34:59 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-11 04:39:02 +0400 |
| commit | 9e350de37ac9607012fcf9c5314a28fbddf8f43c (patch) | |
| tree | d0f311bcf49d887e6d488ea72b2913cb00eaf910 /arch/powerpc | |
| parent | df1a132bf3d3508f863336c80a27806a2ac947e0 (diff) | |
| download | linux-9e350de37ac9607012fcf9c5314a28fbddf8f43c.tar.xz | |
perf_counter: Accurate period data
We currently log hw.sample_period for PERF_SAMPLE_PERIOD, however this is
incorrect. When we adjust the period, it will only take effect the next
cycle but report it for the current cycle. So when we adjust the period
for every cycle, we're always wrong.
Solve this by keeping track of the last_period.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: 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 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/perf_counter.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c index 5e0bf399c433..4990ce2e5f08 100644 --- a/arch/powerpc/kernel/perf_counter.c +++ b/arch/powerpc/kernel/perf_counter.c @@ -767,6 +767,7 @@ static void power_pmu_unthrottle(struct perf_counter *counter) perf_disable(); power_pmu_read(counter); left = counter->hw.sample_period; + counter->hw.last_period = left; val = 0; if (left < 0x80000000L) val = 0x80000000L - left; @@ -937,7 +938,8 @@ const struct pmu *hw_perf_counter_init(struct perf_counter *counter) counter->hw.config = events[n]; counter->hw.counter_base = cflags[n]; - atomic64_set(&counter->hw.period_left, counter->hw.sample_period); + counter->hw.last_period = counter->hw.sample_period; + atomic64_set(&counter->hw.period_left, counter->hw.last_period); /* * See if we need to reserve the PMU. @@ -1002,8 +1004,9 @@ static void record_and_restart(struct perf_counter *counter, long val, */ if (record) { struct perf_sample_data data = { - .regs = regs, - .addr = 0, + .regs = regs, + .addr = 0, + .period = counter->hw.last_period, }; if (counter->attr.sample_type & PERF_SAMPLE_ADDR) { |