diff options
| author | Stephane Eranian | 2017-04-12 11:23:01 -0700 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo | 2017-04-13 10:40:36 -0300 |
| commit | db49a71798a38f3ddf3f3462703328dca39b1ac7 (patch) | |
| tree | c6c7ba37ba155f9e89314f65059f9c3f3a699fcf | |
| parent | 7be6b3166ebf2c10c28ef5777d1b31a937ed8f7a (diff) | |
perf stat: Fix bug in handling events in error state
(This is a patch has been sitting in the Intel CQM/CMT driver series for
a while, despite not depend on it. Sending it now independently since
the series is being discarded.)
When an event is in error state, read() returns 0 instead of sizeof()
buffer. In certain modes, such as interval printing, ignoring the 0
return value may cause bogus count deltas to be computed and thus
invalid results printed.
This patch fixes this problem by modifying read_counters() to mark the
event as not scaled (scaled = -1) to force the printout routine to show
<NOT COUNTED>.
Signed-off-by: Stephane Eranian <eranian@google.com>
Reviewed-by: David Carrillo-Cisneros <davidcc@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170412182301.44406-1-davidcc@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
| -rw-r--r-- | tools/perf/builtin-stat.c | 12 | ||||
| -rw-r--r-- | tools/perf/util/evsel.c | 4 |
2 files changed, 11 insertions, 5 deletions
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 868e086a6b59..610225b6326e 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -312,8 +312,12 @@ static int read_counter(struct perf_evsel *counter) struct perf_counts_values *count; count = perf_counts(counter->counts, cpu, thread); - if (perf_evsel__read(counter, cpu, thread, count)) + if (perf_evsel__read(counter, cpu, thread, count)) { + counter->counts->scaled = -1; + perf_counts(counter->counts, cpu, thread)->ena = 0; + perf_counts(counter->counts, cpu, thread)->run = 0; return -1; + } if (STAT_RECORD) { if (perf_evsel__write_stat_event(counter, cpu, thread, count)) { @@ -338,12 +342,14 @@ static int read_counter(struct perf_evsel *counter) static void read_counters(void) { struct perf_evsel *counter; + int ret; evlist__for_each_entry(evsel_list, counter) { - if (read_counter(counter)) + ret = read_counter(counter); + if (ret) pr_debug("failed to read counter %s\n", counter->name); - if (perf_stat_process_counter(&stat_config, counter)) + if (ret == 0 && perf_stat_process_counter(&stat_config, counter)) pr_warning("failed to process counter %s\n", counter->name); } } diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 8f5d86bd3501..3779b9f3f134 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -1239,7 +1239,7 @@ int perf_evsel__read(struct perf_evsel *evsel, int cpu, int thread, if (FD(evsel, cpu, thread) < 0) return -EINVAL; - if (readn(FD(evsel, cpu, thread), count, sizeof(*count)) < 0) + if (readn(FD(evsel, cpu, thread), count, sizeof(*count)) <= 0) return -errno; return 0; @@ -1257,7 +1257,7 @@ int __perf_evsel__read_on_cpu(struct perf_evsel *evsel, if (evsel->counts == NULL && perf_evsel__alloc_counts(evsel, cpu + 1, thread + 1) < 0) return -ENOMEM; - if (readn(FD(evsel, cpu, thread), &count, nv * sizeof(u64)) < 0) + if (readn(FD(evsel, cpu, thread), &count, nv * sizeof(u64)) <= 0) return -errno; perf_evsel__compute_deltas(evsel, cpu, thread, &count); |