perf intel-pt: Fix snapshot overlap detection decoder errors (810c398b) · Commits · 戴 / test

Fix occasional decoder errors decoding trace data collected in snapshot mode. Snapshot mode can take successive snapshots of trace which might overlap. The decoder checks whether there is an overlap but only looks at the current and previous buffer. However buffers that do not contain synchronization (i.e. PSB) packets cannot be decoded or used for overlap checking. That means the decoder actually needs to check overlaps between the current buffer and the previous buffer that contained usable data. Make that change. Signed-off-by:

Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: stable@vger.kernel.org # v4.3+ Link: http://lkml.kernel.org/r/1474641528-18776-10-git-send-email-adrian.hunter@intel.com Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/intel-pt.c

+11 −4

Original line number	Diff line number	Diff line
		@@ -241,7 +241,7 @@ static int intel_pt_get_trace(struct intel_pt_buffer b, void data)
		}

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

		next:
		buffer = auxtrace_buffer__next(queue, buffer);
		if (!buffer) {
		if (old_buffer)
		@@ -264,9 +264,6 @@ static int intel_pt_get_trace(struct intel_pt_buffer b, void data)
		intel_pt_do_fix_overlap(ptq->pt, old_buffer, buffer))
		return -ENOMEM;

		if (old_buffer)
		auxtrace_buffer__drop_data(old_buffer);

		if (buffer->use_data) {
		b->len = buffer->use_size;
		b->buf = buffer->use_data;
		@@ -276,6 +273,16 @@ static int intel_pt_get_trace(struct intel_pt_buffer b, void data)
		}
		b->ref_timestamp = buffer->reference;

		/*
		* If in snapshot mode and the buffer has no usable data, get next
		* buffer and again check overlap against old_buffer.
		*/
		if (ptq->pt->snapshot_mode && !b->len)
		goto next;

		if (old_buffer)
		auxtrace_buffer__drop_data(old_buffer);

		if (!old_buffer \|\| ptq->pt->sampling_mode \|\| (ptq->pt->snapshot_mode &&
		!buffer->consecutive)) {
		b->consecutive = false;

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