Commit 810c398b authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo

perf intel-pt: Fix snapshot overlap detection decoder errors

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: default avatarAdrian 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.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent f9655200
......@@ -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;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment