From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: <linux-kernel@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org
Subject: [PATCH 02/10] perf: Split perf_event_read() and perf_event_count()
Date: Sun, 26 Jul 2015 22:40:30 -0700 [thread overview]
Message-ID: <1437975638-789-3-git-send-email-sukadev@linux.vnet.ibm.com> (raw)
In-Reply-To: <1437975638-789-1-git-send-email-sukadev@linux.vnet.ibm.com>
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@linux.vnet.ibm.com>
---
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 4435bf5..f9ca8cb 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3212,7 +3212,7 @@ static inline u64 perf_event_count(struct perf_event *event)
return __perf_event_count(event);
}
-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
@@ -3238,8 +3238,6 @@ 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);
}
/*
@@ -3751,14 +3749,18 @@ 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;
}
@@ -3918,7 +3920,7 @@ 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);
}
--
1.7.9.5
next prev parent reply other threads:[~2015-07-27 5:42 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-27 5:40 [PATCH v4 0/10] Implement group-read of events using txn interface Sukadev Bhattiprolu
2015-07-27 5:40 ` [PATCH 01/10] perf: Add a flags parameter to pmu txn interfaces Sukadev Bhattiprolu
2015-07-27 5:40 ` Sukadev Bhattiprolu [this message]
2015-07-27 5:40 ` [PATCH 03/10] perf: Define perf_event_aggregate() Sukadev Bhattiprolu
2015-07-27 5:40 ` [PATCH 04/10] perf: Rename perf_event_read_{one,group}, perf_read_hw Sukadev Bhattiprolu
2015-07-27 5:40 ` [PATCH 05/10] perf: Unroll perf_event_read_value() in perf_read_group() Sukadev Bhattiprolu
2015-07-27 5:40 ` [PATCH 06/10] perf: Add return value for perf_event_read() Sukadev Bhattiprolu
2015-07-27 5:40 ` [PATCH 07/10] perf: Add group parameter to perf_event_read() Sukadev Bhattiprolu
2015-07-27 5:40 ` [PATCH 08/10] perf: Add return value to __perf_event_read() Sukadev Bhattiprolu
2015-07-27 5:40 ` [PATCH 09/10] Define PERF_PMU_TXN_READ interface Sukadev Bhattiprolu
2015-08-06 12:10 ` Peter Zijlstra
2015-08-12 4:14 ` Sukadev Bhattiprolu
2015-08-12 8:45 ` Peter Zijlstra
2015-08-13 20:04 ` Sukadev Bhattiprolu
2015-08-13 20:47 ` Peter Zijlstra
2015-07-27 5:40 ` [PATCH 10/10] powerpc/perf/hv-24x7: Use PMU_TXN_READ interface Sukadev Bhattiprolu
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