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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-06-10 21:34:59 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-11 02:39:02 +0200
commit9e350de37ac9607012fcf9c5314a28fbddf8f43c (patch)
treed0f311bcf49d887e6d488ea72b2913cb00eaf910 /arch/powerpc
parentdf1a132bf3d3508f863336c80a27806a2ac947e0 (diff)
downloadlinux-2.6.34-ux500-9e350de37ac9607012fcf9c5314a28fbddf8f43c.tar.gz
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.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c
index 5e0bf399c43..4990ce2e5f0 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) {