From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752646AbcHOH1p (ORCPT ); Mon, 15 Aug 2016 03:27:45 -0400 Received: from mga14.intel.com ([192.55.52.115]:13264 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752359AbcHOH1o (ORCPT ); Mon, 15 Aug 2016 03:27:44 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.28,524,1464678000"; d="scan'208";a="865526433" From: Adrian Hunter To: Arnaldo Carvalho de Melo Cc: Jiri Olsa , linux-kernel@vger.kernel.org Subject: [PATCH] perf intel-pt: Fix occasional decoding errors when tracing system-wide Date: Mon, 15 Aug 2016 10:23:04 +0300 Message-Id: <1471245784-22580-1-git-send-email-adrian.hunter@intel.com> X-Mailer: git-send-email 1.9.1 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 In order to successfully decode Intel PT traces, context switch events are needed from the moment the trace starts. Currently that is ensured by using the 'immediate' flag which enables the switch event when it is opened. However, since commit 86c2786994bd ("perf intel-pt: Add support for PERF_RECORD_SWITCH") that might not always happen. When tracing system-wide the context switch event is added to the tracking event which was not set as 'immediate'. Change that so it is. Signed-off-by: Adrian Hunter Fixes: 86c2786994bd ("perf intel-pt: Add support for PERF_RECORD_SWITCH") Cc: stable@vger.kernel.org # v4.4+ --- tools/perf/arch/x86/util/intel-pt.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/perf/arch/x86/util/intel-pt.c b/tools/perf/arch/x86/util/intel-pt.c index fb51457ba338..a2412e9d883b 100644 --- a/tools/perf/arch/x86/util/intel-pt.c +++ b/tools/perf/arch/x86/util/intel-pt.c @@ -501,7 +501,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, struct intel_pt_recording *ptr = container_of(itr, struct intel_pt_recording, itr); struct perf_pmu *intel_pt_pmu = ptr->intel_pt_pmu; - bool have_timing_info; + bool have_timing_info, need_immediate = false; struct perf_evsel *evsel, *intel_pt_evsel = NULL; const struct cpu_map *cpus = evlist->cpus; bool privileged = geteuid() == 0 || perf_event_paranoid() < 0; @@ -655,6 +655,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, ptr->have_sched_switch = 3; } else { opts->record_switch_events = true; + need_immediate = true; if (cpu_wide) ptr->have_sched_switch = 3; else @@ -700,6 +701,9 @@ static int intel_pt_recording_options(struct auxtrace_record *itr, tracking_evsel->attr.freq = 0; tracking_evsel->attr.sample_period = 1; + if (need_immediate) + tracking_evsel->immediate = true; + /* In per-cpu case, always need the time of mmap events etc */ if (!cpu_map__empty(cpus)) { perf_evsel__set_sample_bit(tracking_evsel, TIME); -- 1.9.1