From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934527AbcI2OkS (ORCPT ); Thu, 29 Sep 2016 10:40:18 -0400 Received: from merlin.infradead.org ([205.233.59.134]:47436 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933710AbcI2OgY (ORCPT ); Thu, 29 Sep 2016 10:36:24 -0400 From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Linux Weekly News , Adrian Hunter , Jiri Olsa , Masami Hiramatsu , Mathieu Poirier , stable@vger.kernel.org, #@infradead.org, v4.3+@infradead.org, Arnaldo Carvalho de Melo Subject: [PATCH 15/27] perf intel-pt: Fix snapshot overlap detection decoder errors Date: Thu, 29 Sep 2016 11:35:44 -0300 Message-Id: <1475159756-21326-16-git-send-email-acme@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1475159756-21326-1-git-send-email-acme@kernel.org> References: <1475159756-21326-1-git-send-email-acme@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by merlin.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Adrian Hunter 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 Cc: Jiri Olsa Cc: Masami Hiramatsu Cc: Mathieu Poirier 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 --- tools/perf/util/intel-pt.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c index b9cc353cace2..b744ea812a2e 100644 --- a/tools/perf/util/intel-pt.c +++ b/tools/perf/util/intel-pt.c @@ -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; -- 2.7.4