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| author | Eric B Munson <emunson@mgebm.net> | 2011-06-23 16:34:38 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-07-01 11:06:33 +0200 |
| commit | c4794295917ebeda8013b6cb9c8d71ab4f74a1fa (patch) | |
| tree | bb422e3368f2ad686e69229b416536b2bcb1df8e /kernel/events/core.c | |
| parent | b7526f0ca6dc68f57ca467ce503151b1d476a3e4 (diff) | |
| download | lwn-c4794295917ebeda8013b6cb9c8d71ab4f74a1fa.tar.gz lwn-c4794295917ebeda8013b6cb9c8d71ab4f74a1fa.zip | |
events: Move lockless timer calculation into helper function
Take the timer calculation from perf_output_read and move it to a helper
function for any place that needs timer values but cannot take the ctx->lock.
Signed-off-by: Eric B Munson <emunson@mgebm.net>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1308861279-15216-2-git-send-email-emunson@mgebm.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/events/core.c')
| -rw-r--r-- | kernel/events/core.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 2293e0b084a9..c851d707821f 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3351,6 +3351,18 @@ static int perf_event_index(struct perf_event *event) return event->hw.idx + 1 - PERF_EVENT_INDEX_OFFSET; } +static void calc_timer_values(struct perf_event *event, + u64 *running, + u64 *enabled) +{ + u64 now, ctx_time; + + now = perf_clock(); + ctx_time = event->shadow_ctx_time + now; + *enabled = ctx_time - event->tstamp_enabled; + *running = ctx_time - event->tstamp_running; +} + /* * Callers need to ensure there can be no nesting of this function, otherwise * the seqlock logic goes bad. We can not serialize this because the arch @@ -3816,7 +3828,7 @@ static void perf_output_read_group(struct perf_output_handle *handle, static void perf_output_read(struct perf_output_handle *handle, struct perf_event *event) { - u64 enabled = 0, running = 0, now, ctx_time; + u64 enabled = 0, running = 0; u64 read_format = event->attr.read_format; /* @@ -3828,12 +3840,8 @@ static void perf_output_read(struct perf_output_handle *handle, * because of locking issue as we are called in * NMI context */ - if (read_format & PERF_FORMAT_TOTAL_TIMES) { - now = perf_clock(); - ctx_time = event->shadow_ctx_time + now; - enabled = ctx_time - event->tstamp_enabled; - running = ctx_time - event->tstamp_running; - } + if (read_format & PERF_FORMAT_TOTAL_TIMES) + calc_timer_values(event, &enabled, &running); if (event->attr.read_format & PERF_FORMAT_GROUP) perf_output_read_group(handle, event, enabled, running); |