| From 3d918fb13abdbeca7947578f5d7e426eafad7f5e Mon Sep 17 00:00:00 2001 |
| From: Adrian Hunter <adrian.hunter@intel.com> |
| Date: Mon, 15 Aug 2016 10:23:04 +0300 |
| Subject: perf intel-pt: Fix occasional decoding errors when tracing system-wide |
| |
| From: Adrian Hunter <adrian.hunter@intel.com> |
| |
| commit 3d918fb13abdbeca7947578f5d7e426eafad7f5e upstream. |
| |
| 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 <adrian.hunter@intel.com> |
| Cc: Jiri Olsa <jolsa@redhat.com> |
| Fixes: 86c2786994bd ("perf intel-pt: Add support for PERF_RECORD_SWITCH") |
| Link: http://lkml.kernel.org/r/1471245784-22580-1-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> |
| |
| --- |
| tools/perf/arch/x86/util/intel-pt.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| --- 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(st |
| 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(st |
| 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(st |
| 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); |
