Commit-ID: db49a71798a38f3ddf3f3462703328dca39b1ac7
Gitweb: http://git.kernel.org/tip/db49a71798a38f3ddf3f3462703328dca39b1ac7
Author: Stephane Eranian <eranian@xxxxxxxxxx>
AuthorDate: Wed, 12 Apr 2017 11:23:01 -0700
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 13 Apr 2017 10:40:36 -0300
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@xxxxxxxxxx>
Reviewed-by: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20170412182301.44406-1-davidcc@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-stat.c | 12 +++++++++---
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 868e086a..610225b 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 8f5d86b..3779b9f 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);
--
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