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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>
hifive-unleashed-5.1
Stephane Eranian 2010-08-26 16:40:01 +02:00 committed by Ingo Molnar
parent 5225c45899
commit fa66f07aa1
1 changed files with 22 additions and 4 deletions
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26
kernel/perf_event.c
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@ -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;
}