Commit c457810a authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Orig-LKML-Reference: <20090402091319.323309784@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 8a057d84

include/linux/perf_counter.h

+2 −1
Original line number Diff line number Diff line
@@ -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];

};

kernel/perf_counter.c

+9 −1
Original line number Diff line number Diff line
@@ -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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