summaryrefslogtreecommitdiff
path: root/kernel/events
diff options
context:
space:
mode:
authorSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>2015-09-03 20:07:51 -0700
committerIngo Molnar <mingo@kernel.org>2015-09-13 11:27:28 +0200
commit4a00c16e552ea5e71756cd29cd2df7557ec9cac4 (patch)
tree05e3a180a8e8cc5ba8504046141c8084bb727e7c /kernel/events
parent7d88962e230c8342080e7e2fe9dd5be43dc13b79 (diff)
perf/core: Define PERF_PMU_TXN_READ interface
Define a new PERF_PMU_TXN_READ interface to read a group of counters at once. pmu->start_txn() // Initialize before first event for each event in group pmu->read(event); // Queue each event to be read rc = pmu->commit_txn() // Read/update all queued counters Note that we use this interface with all PMUs. PMUs that implement this interface use the ->read() operation to _queue_ the counters to be read and use ->commit_txn() to actually read all the queued counters at once. PMUs that don't implement PERF_PMU_TXN_READ ignore ->start_txn() and ->commit_txn() and continue to read counters one at a time. Thanks to input from Peter Zijlstra. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-9-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c24
1 files changed, 19 insertions, 5 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index ade04dfab368..55b0f7cf2614 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3199,6 +3199,7 @@ static void __perf_event_read(void *info)
struct perf_event *sub, *event = data->event;
struct perf_event_context *ctx = event->ctx;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
+ struct pmu *pmu = event->pmu;
/*
* If this is a task context, we need to check whether it is
@@ -3217,18 +3218,31 @@ static void __perf_event_read(void *info)
}
update_event_times(event);
- if (event->state == PERF_EVENT_STATE_ACTIVE)
- event->pmu->read(event);
+ if (event->state != PERF_EVENT_STATE_ACTIVE)
+ goto unlock;
- if (!data->group)
+ if (!data->group) {
+ pmu->read(event);
+ data->ret = 0;
goto unlock;
+ }
+
+ pmu->start_txn(pmu, PERF_PMU_TXN_READ);
+
+ pmu->read(event);
list_for_each_entry(sub, &event->sibling_list, group_entry) {
update_event_times(sub);
- if (sub->state == PERF_EVENT_STATE_ACTIVE)
+ if (sub->state == PERF_EVENT_STATE_ACTIVE) {
+ /*
+ * Use sibling's PMU rather than @event's since
+ * sibling could be on different (eg: software) PMU.
+ */
sub->pmu->read(sub);
+ }
}
- data->ret = 0;
+
+ data->ret = pmu->commit_txn(pmu);
unlock:
raw_spin_unlock(&ctx->lock);