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Commit da9000ae authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
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perf intel-pt: Add support for lookahead 



Implement the lookahead callback to let the decoder access subsequent
buffers. intel_pt_lookahead() manages the buffer lifetime and calls the
decoder for each buffer until the decoder returns a non-zero value.

Signed-off-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190604130017.31207-11-adrian.hunter@intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e96f7df8

tools/perf/util/intel-pt.c

+58 −1
Original line number Diff line number Diff line
@@ -278,7 +278,63 @@ static int intel_pt_get_buffer(struct intel_pt_queue *ptq, 
	return 0;

}



/* This function assumes data is processed sequentially only */

/* Do not drop buffers with references - refer intel_pt_get_trace() */

static void intel_pt_lookahead_drop_buffer(struct intel_pt_queue *ptq,

					   struct auxtrace_buffer *buffer)

{

	if (!buffer || buffer == ptq->buffer || buffer == ptq->old_buffer)

		return;



	auxtrace_buffer__drop_data(buffer);

}



/* Must be serialized with respect to intel_pt_get_trace() */

static int intel_pt_lookahead(void *data, intel_pt_lookahead_cb_t cb,

			      void *cb_data)

{

	struct intel_pt_queue *ptq = data;

	struct auxtrace_buffer *buffer = ptq->buffer;

	struct auxtrace_buffer *old_buffer = ptq->old_buffer;

	struct auxtrace_queue *queue;

	int err = 0;



	queue = &ptq->pt->queues.queue_array[ptq->queue_nr];



	while (1) {

		struct intel_pt_buffer b = { .len = 0 };



		buffer = auxtrace_buffer__next(queue, buffer);

		if (!buffer)

			break;



		err = intel_pt_get_buffer(ptq, buffer, old_buffer, &b);

		if (err)

			break;



		if (b.len) {

			intel_pt_lookahead_drop_buffer(ptq, old_buffer);

			old_buffer = buffer;

		} else {

			intel_pt_lookahead_drop_buffer(ptq, buffer);

			continue;

		}



		err = cb(&b, cb_data);

		if (err)

			break;

	}



	if (buffer != old_buffer)

		intel_pt_lookahead_drop_buffer(ptq, buffer);

	intel_pt_lookahead_drop_buffer(ptq, old_buffer);



	return err;

}



/*

 * This function assumes data is processed sequentially only.

 * Must be serialized with respect to intel_pt_lookahead()

 */

static int intel_pt_get_trace(struct intel_pt_buffer *b, void *data)

{

	struct intel_pt_queue *ptq = data;
@@ -827,6 +883,7 @@ static struct intel_pt_queue *intel_pt_alloc_queue(struct intel_pt *pt, 


	params.get_trace = intel_pt_get_trace;

	params.walk_insn = intel_pt_walk_next_insn;

	params.lookahead = intel_pt_lookahead;

	params.data = ptq;

	params.return_compression = intel_pt_return_compression(pt);

	params.branch_enable = intel_pt_branch_enable(pt);