Commit-ID: 443772776c69ac9293d66b4d69fd9af16299cc2a
Gitweb: http://git.kernel.org/tip/443772776c69ac9293d66b4d69fd9af16299cc2a
Author: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 16 Dec 2013 14:17:36 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 17 Dec 2013 15:04:00 +0100
perf: Disable all pmus on unthrottling and rescheduling
Currently, only one PMU in a context gets disabled during unthrottling
and event_sched_{out,in}(), however, events in one context may belong to
different pmus, which results in PMUs being reprogrammed while they are
still enabled.
This means that mixed PMU use [which is rare in itself] resulted in
potentially completely unreliable results: corrupted events, bogus
results, etc.
This patch temporarily disables PMUs that correspond to
each event in the context while these events are being modified.
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1387196256-8030-1-git-send-email-alexander.shishkin@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 21 ++++++++++++++++++---
1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 72348dc..f574401 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1396,6 +1396,8 @@ event_sched_out(struct perf_event *event,
if (event->state != PERF_EVENT_STATE_ACTIVE)
return;
+ perf_pmu_disable(event->pmu);
+
event->state = PERF_EVENT_STATE_INACTIVE;
if (event->pending_disable) {
event->pending_disable = 0;
@@ -1412,6 +1414,8 @@ event_sched_out(struct perf_event *event,
ctx->nr_freq--;
if (event->attr.exclusive || !cpuctx->active_oncpu)
cpuctx->exclusive = 0;
+
+ perf_pmu_enable(event->pmu);
}
static void
@@ -1652,6 +1656,7 @@ event_sched_in(struct perf_event *event,
struct perf_event_context *ctx)
{
u64 tstamp = perf_event_time(event);
+ int ret = 0;
if (event->state <= PERF_EVENT_STATE_OFF)
return 0;
@@ -1674,10 +1679,13 @@ event_sched_in(struct perf_event *event,
*/
smp_wmb();
+ perf_pmu_disable(event->pmu);
+
if (event->pmu->add(event, PERF_EF_START)) {
event->state = PERF_EVENT_STATE_INACTIVE;
event->oncpu = -1;
- return -EAGAIN;
+ ret = -EAGAIN;
+ goto out;
}
event->tstamp_running += tstamp - event->tstamp_stopped;
@@ -1693,7 +1701,10 @@ event_sched_in(struct perf_event *event,
if (event->attr.exclusive)
cpuctx->exclusive = 1;
- return 0;
+out:
+ perf_pmu_enable(event->pmu);
+
+ return ret;
}
static int
@@ -2743,6 +2754,8 @@ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
if (!event_filter_match(event))
continue;
+ perf_pmu_disable(event->pmu);
+
hwc = &event->hw;
if (hwc->interrupts == MAX_INTERRUPTS) {
@@ -2752,7 +2765,7 @@ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
}
if (!event->attr.freq || !event->attr.sample_freq)
- continue;
+ goto next;
/*
* stop the event and update event->count
@@ -2774,6 +2787,8 @@ static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
perf_adjust_period(event, period, delta, false);
event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
+ next:
+ perf_pmu_enable(event->pmu);
}
perf_pmu_enable(ctx->pmu);
--
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