Commit-ID: e5302920da9ef23f9d19d4e9ac85704cc25bee7a
Gitweb: http://git.kernel.org/tip/e5302920da9ef23f9d19d4e9ac85704cc25bee7a
Author: Stephane Eranian <eranian@xxxxxxxxxx>
AuthorDate: Fri, 5 Jul 2013 00:30:11 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 5 Jul 2013 08:54:43 +0200
perf: Fix interrupt handler timing harness
This patch fixes a serious bug in:
14c63f17b1fd perf: Drop sample rate when sampling is too slow
There was an misunderstanding on the API of the do_div()
macro. It returns the remainder of the division and this
was not what the function expected leading to disabling the
interrupt latency watchdog.
This patch also remove a duplicate assignment in
perf_sample_event_took().
Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Cc: dave.hansen@xxxxxxxxxxxxxxx
Cc: ak@xxxxxxxxxxxxxxx
Cc: jolsa@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20130704223010.GA30625@quad
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1db3af9..1833bc5 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -182,7 +182,7 @@ void update_perf_cpu_limits(void)
u64 tmp = perf_sample_period_ns;
tmp *= sysctl_perf_cpu_time_max_percent;
- tmp = do_div(tmp, 100);
+ do_div(tmp, 100);
atomic_set(&perf_sample_allowed_ns, tmp);
}
@@ -232,7 +232,7 @@ DEFINE_PER_CPU(u64, running_sample_length);
void perf_sample_event_took(u64 sample_len_ns)
{
u64 avg_local_sample_len;
- u64 local_samples_len = __get_cpu_var(running_sample_length);
+ u64 local_samples_len;
if (atomic_read(&perf_sample_allowed_ns) == 0)
return;
--
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