From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1035109AbcIWOn4 (ORCPT ); Fri, 23 Sep 2016 10:43:56 -0400 Received: from mga05.intel.com ([192.55.52.43]:46070 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1035088AbcIWOns (ORCPT ); Fri, 23 Sep 2016 10:43:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,381,1470726000"; d="scan'208";a="1044690177" From: Adrian Hunter To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , Masami Hiramatsu , Mathieu Poirier , linux-kernel@vger.kernel.org Subject: [PATCH 09/16] perf intel-pt: Fix snapshot overlap detection decoder errors Date: Fri, 23 Sep 2016 17:38:41 +0300 Message-Id: <1474641528-18776-10-git-send-email-adrian.hunter@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1474641528-18776-1-git-send-email-adrian.hunter@intel.com> References: <1474641528-18776-1-git-send-email-adrian.hunter@intel.com> Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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: stable@vger.kernel.org # v4.3+ --- 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; -- 1.9.1