Commit-ID: b202978dae5fce00d19480360f165a181be19704
Gitweb: http://git.kernel.org/tip/b202978dae5fce00d19480360f165a181be19704
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Thu, 2 Apr 2009 11:12:01 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 2 Apr 2009 13:52:59 +0200
perf_counter: per event wakeups
By request, provide a way to request a wakeup every 'n' events instead
of every page of output.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Corey Ashford <cjashfor@xxxxxxxxxxxxxxxxxx>
LKML-Reference: <20090402091319.323309784@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
include/linux/perf_counter.h | 3 ++-
kernel/perf_counter.c | 10 +++++++++-
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 06a6fba..5428ba1 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -145,7 +145,7 @@ struct perf_counter_hw_event {
__reserved_1 : 53;
__u32 extra_config_len;
- __u32 __reserved_4;
+ __u32 wakeup_events; /* wakeup every n events */
__u64 __reserved_2;
__u64 __reserved_3;
@@ -321,6 +321,7 @@ struct perf_mmap_data {
int nr_pages;
atomic_t wakeup;
atomic_t head;
+ atomic_t events;
struct perf_counter_mmap_page *user_page;
void *data_pages[0];
};
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 995063d..9bcab10 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1760,7 +1760,15 @@ static void perf_output_copy(struct perf_output_handle *handle,
static void perf_output_end(struct perf_output_handle *handle)
{
- if (handle->wakeup)
+ int wakeup_events = handle->counter->hw_event.wakeup_events;
+
+ if (wakeup_events) {
+ int events = atomic_inc_return(&handle->data->events);
+ if (events >= wakeup_events) {
+ atomic_sub(wakeup_events, &handle->data->events);
+ __perf_output_wakeup(handle);
+ }
+ } else if (handle->wakeup)
__perf_output_wakeup(handle);
rcu_read_unlock();
}
--
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