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authorStephane Eranian <eranian@google.com>2013-07-05 00:30:11 +0200
committerIngo Molnar <mingo@kernel.org>2013-07-05 08:54:43 +0200
commite5302920da9ef23f9d19d4e9ac85704cc25bee7a (patch)
treebea762940dbb32ec98e99de896ad3a6d450cc025 /kernel
parent100ac5331519866afa9b000b10642b00cb6d03dd (diff)
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@google.com> Cc: peterz@infradead.org Cc: dave.hansen@linux.intel.com Cc: ak@linux.intel.com Cc: jolsa@redhat.com Link: http://lkml.kernel.org/r/20130704223010.GA30625@quad Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1db3af933704..1833bc5a84a7 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;