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Commit a5cdd40c authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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perf: Update perf_event_type documentation 



Due to a discussion with Adrian I had a good look at the perf_event_type record
layout and found the documentation to be somewhat unclear.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130716150907.GL23818@dyad.programming.kicks-ass.net


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 17f41571

include/uapi/linux/perf_event.h

+17 −1
Original line number Diff line number Diff line
@@ -478,6 +478,16 @@ enum perf_event_type { 
	 * file will be supported by older perf tools, with these new optional

	 * fields being ignored.

	 *

	 * struct sample_id {

	 * 	{ u32			pid, tid; } && PERF_SAMPLE_TID

	 * 	{ u64			time;     } && PERF_SAMPLE_TIME

	 * 	{ u64			id;       } && PERF_SAMPLE_ID

	 * 	{ u64			stream_id;} && PERF_SAMPLE_STREAM_ID

	 * 	{ u32			cpu, res; } && PERF_SAMPLE_CPU

	 * } && perf_event_attr::sample_id_all

	 */



	/*

	 * The MMAP events record the PROT_EXEC mappings so that we can

	 * correlate userspace IPs to code. They have the following structure:

	 *
@@ -498,6 +508,7 @@ enum perf_event_type { 
	 *	struct perf_event_header	header;

	 *	u64				id;

	 *	u64				lost;

	 * 	struct sample_id		sample_id;

	 * };

	 */

	PERF_RECORD_LOST			= 2,
@@ -508,6 +519,7 @@ enum perf_event_type { 
	 *

	 *	u32				pid, tid;

	 *	char				comm[];

	 * 	struct sample_id		sample_id;

	 * };

	 */

	PERF_RECORD_COMM			= 3,
@@ -518,6 +530,7 @@ enum perf_event_type { 
	 *	u32				pid, ppid;

	 *	u32				tid, ptid;

	 *	u64				time;

	 * 	struct sample_id		sample_id;

	 * };

	 */

	PERF_RECORD_EXIT			= 4,
@@ -528,6 +541,7 @@ enum perf_event_type { 
	 *	u64				time;

	 *	u64				id;

	 *	u64				stream_id;

	 * 	struct sample_id		sample_id;

	 * };

	 */

	PERF_RECORD_THROTTLE			= 5,
@@ -539,6 +553,7 @@ enum perf_event_type { 
	 *	u32				pid, ppid;

	 *	u32				tid, ptid;

	 *	u64				time;

	 * 	struct sample_id		sample_id;

	 * };

	 */

	PERF_RECORD_FORK			= 7,
@@ -549,6 +564,7 @@ enum perf_event_type { 
	 *	u32				pid, tid;

	 *

	 *	struct read_format		values;

	 * 	struct sample_id		sample_id;

	 * };

	 */

	PERF_RECORD_READ			= 8,

kernel/events/core.c

+16 −15
Original line number Diff line number Diff line
@@ -4462,20 +4462,6 @@ void perf_output_sample(struct perf_output_handle *handle, 
		}

	}



	if (!event->attr.watermark) {

		int wakeup_events = event->attr.wakeup_events;



		if (wakeup_events) {

			struct ring_buffer *rb = handle->rb;

			int events = local_inc_return(&rb->events);



			if (events >= wakeup_events) {

				local_sub(wakeup_events, &rb->events);

				local_inc(&rb->wakeup);

			}

		}

	}



	if (sample_type & PERF_SAMPLE_BRANCH_STACK) {

		if (data->br_stack) {

			size_t size;
@@ -4511,16 +4497,31 @@ void perf_output_sample(struct perf_output_handle *handle, 
		}

	}



	if (sample_type & PERF_SAMPLE_STACK_USER)

	if (sample_type & PERF_SAMPLE_STACK_USER) {

		perf_output_sample_ustack(handle,

					  data->stack_user_size,

					  data->regs_user.regs);

	}



	if (sample_type & PERF_SAMPLE_WEIGHT)

		perf_output_put(handle, data->weight);



	if (sample_type & PERF_SAMPLE_DATA_SRC)

		perf_output_put(handle, data->data_src.val);



	if (!event->attr.watermark) {

		int wakeup_events = event->attr.wakeup_events;



		if (wakeup_events) {

			struct ring_buffer *rb = handle->rb;

			int events = local_inc_return(&rb->events);



			if (events >= wakeup_events) {

				local_sub(wakeup_events, &rb->events);

				local_inc(&rb->wakeup);

			}

		}

	}

}



void perf_prepare_sample(struct perf_event_header *header,