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authorAdrian Hunter <adrian.hunter@intel.com>2016-09-23 17:38:41 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-10-28 03:01:27 -0400
commit0ea2bdfcdd0e10783a6f5bd0834934e506ec3b65 (patch)
treeaf9aad99bb3b51da349bfc5a16dc14d65fa0fc5c /tools
parent987ec3eb8f6360d43be358ebb9e350114bc78a32 (diff)
perf intel-pt: Fix snapshot overlap detection decoder errors
commit 810c398bc09b2f2dfde52a7d2483a710612c5fb8 upstream. 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> 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/intel-pt.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 9227c2f076c3..89927b5beebf 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -238,7 +238,7 @@ 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)
@@ -261,9 +261,6 @@ 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;
@@ -273,6 +270,16 @@ 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;