Commit-ID: 01add3eaf1b25e497b14ca210f3bfe5f5dd2b112
Gitweb: http://git.kernel.org/tip/01add3eaf1b25e497b14ca210f3bfe5f5dd2b112
Author: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu, 3 Sep 2015 20:07:46 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 13 Sep 2015 11:27:25 +0200
perf/core: Split perf_event_read() and perf_event_count()
perf_event_read() does two things:
- call the PMU to read/update the counter value, and
- compute the total count of the event and its children
Not all callers need both. perf_event_reset() for instance needs the
first piece but doesn't need the second. Similarly, when we implement
the ability to read a group of events using the transaction interface,
we would need the two pieces done independently.
Break up perf_event_read() and have it just read/update the counter
and have the callers compute the total count if necessary.
Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1441336073-22750-4-git-send-email-sukadev@xxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c80cee8..260bf8c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3275,7 +3275,7 @@ u64 perf_event_read_local(struct perf_event *event)
return val;
}
-static u64 perf_event_read(struct perf_event *event)
+static void perf_event_read(struct perf_event *event)
{
/*
* If event is enabled and currently active on a CPU, update the
@@ -3301,8 +3301,6 @@ static u64 perf_event_read(struct perf_event *event)
update_event_times(event);
raw_spin_unlock_irqrestore(&ctx->lock, flags);
}
-
- return perf_event_count(event);
}
/*
@@ -3818,14 +3816,18 @@ u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
*running = 0;
mutex_lock(&event->child_mutex);
- total += perf_event_read(event);
+
+ perf_event_read(event);
+ total += perf_event_count(event);
+
*enabled += event->total_time_enabled +
atomic64_read(&event->child_total_time_enabled);
*running += event->total_time_running +
atomic64_read(&event->child_total_time_running);
list_for_each_entry(child, &event->child_list, child_list) {
- total += perf_event_read(child);
+ perf_event_read(child);
+ total += perf_event_count(child);
*enabled += child->total_time_enabled;
*running += child->total_time_running;
}
@@ -3985,7 +3987,7 @@ static unsigned int perf_poll(struct file *file, poll_table *wait)
static void _perf_event_reset(struct perf_event *event)
{
- (void)perf_event_read(event);
+ perf_event_read(event);
local64_set(&event->count, 0);
perf_event_update_userpage(event);
}
--
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