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authorStephane Eranian <eranian@google.com>2010-08-26 16:40:01 +0200
committerIngo Molnar <mingo@elte.hu>2010-08-30 12:16:55 +0200
commitfa66f07aa1f0950e1dc78b7ab39728b3f8aa77a1 (patch)
tree4ad4612c2fc07f159e192fae9145f9d87a697592 /kernel
parent5225c45899e872383ca39f5533d28ec63c54b39e (diff)
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perf_events: Fix time tracking for events with pid != -1 and cpu != -1
Per-thread events with a cpu filter, i.e., cpu != -1, were not reporting correct timings when the thread never ran on the monitored cpu. The time enabled was reported as a negative value. This patch fixes the problem by updating tstamp_stopped, tstamp_running in event_sched_out() for events with filters and which are marked as INACTIVE. The function group_sched_out() is modified to systematically call into event_sched_out() to avoid duplicating the timing adjustment code twice. With the patch, I now get: $ task_cpu -i -e unhalted_core_cycles,unhalted_core_cycles noploop 2 noploop for 2 seconds CPU0 0 unhalted_core_cycles (ena=1,991,136,594, run=0) CPU0 0 unhalted_core_cycles (ena=1,991,136,594, run=0) CPU1 0 unhalted_core_cycles (ena=1,991,136,594, run=0) CPU1 0 unhalted_core_cycles (ena=1,991,136,594, run=0) CPU2 0 unhalted_core_cycles (ena=1,991,136,594, run=0) CPU2 0 unhalted_core_cycles (ena=1,991,136,594, run=0) CPU3 4,747,990,931 unhalted_core_cycles (ena=1,991,136,594, run=1,991,136,594) CPU3 4,747,990,931 unhalted_core_cycles (ena=1,991,136,594, run=1,991,136,594) Signed-off-by: Stephane Eranian <eranian@gmail.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: paulus@samba.org Cc: davem@davemloft.net Cc: fweisbec@gmail.com Cc: perfmon2-devel@lists.sf.net Cc: eranian@google.com LKML-Reference: <4c76802d.aae9d80a.115d.70fe@mx.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/perf_event.c26
1 files changed, 22 insertions, 4 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 403d1804b19..657555a5f30 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -402,11 +402,31 @@ static void perf_group_detach(struct perf_event *event)
}
}
+static inline int
+event_filter_match(struct perf_event *event)
+{
+ return event->cpu == -1 || event->cpu == smp_processor_id();
+}
+
static void
event_sched_out(struct perf_event *event,
struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx)
{
+ u64 delta;
+ /*
+ * An event which could not be activated because of
+ * filter mismatch still needs to have its timings
+ * maintained, otherwise bogus information is return
+ * via read() for time_enabled, time_running:
+ */
+ if (event->state == PERF_EVENT_STATE_INACTIVE
+ && !event_filter_match(event)) {
+ delta = ctx->time - event->tstamp_stopped;
+ event->tstamp_running += delta;
+ event->tstamp_stopped = ctx->time;
+ }
+
if (event->state != PERF_EVENT_STATE_ACTIVE)
return;
@@ -432,9 +452,7 @@ group_sched_out(struct perf_event *group_event,
struct perf_event_context *ctx)
{
struct perf_event *event;
-
- if (group_event->state != PERF_EVENT_STATE_ACTIVE)
- return;
+ int state = group_event->state;
event_sched_out(group_event, cpuctx, ctx);
@@ -444,7 +462,7 @@ group_sched_out(struct perf_event *group_event,
list_for_each_entry(event, &group_event->sibling_list, group_entry)
event_sched_out(event, cpuctx, ctx);
- if (group_event->attr.exclusive)
+ if (state == PERF_EVENT_STATE_ACTIVE && group_event->attr.exclusive)
cpuctx->exclusive = 0;
}