perf stat: Don't show counter information when workload fails
When starting a workload 'stat' wasn't using prepare_workload evlist
method's signal based exec() error reporting mechanism.
Use it so that the we don't report 'not counted' counters.
Before:
[acme@zoo linux]$ perf stat dfadsfa
dfadsfa: No such file or directory
Performance counter stats for 'dfadsfa':
<not counted> task-clock
<not counted> context-switches
<not counted> cpu-migrations
<not counted> page-faults
<not counted> cycles
<not counted> stalled-cycles-frontend
<not supported> stalled-cycles-backend
<not counted> instructions
<not counted> branches
<not counted> branch-misses
0.001831462 seconds time elapsed
[acme@zoo linux]$
After:
[acme@zoo linux]$ perf stat dfadsfa
dfadsfa: No such file or directory
[acme@zoo linux]$
Reported-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-5yui3bv7e3hitxucnjsn6z8q@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 106a5e5..1c76c7a 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -509,6 +509,18 @@
}
}
+static volatile bool workload_exec_failed;
+
+/*
+ * perf_evlist__prepare_workload will send a SIGUSR1
+ * if the fork fails, since we asked by setting its
+ * want_signal to true.
+ */
+static void workload_exec_failed_signal(int signo __maybe_unused)
+{
+ workload_exec_failed = true;
+}
+
static int __run_perf_stat(int argc, const char **argv)
{
char msg[512];
@@ -529,7 +541,7 @@
if (forks) {
if (perf_evlist__prepare_workload(evsel_list, &target, argv,
- false, false) < 0) {
+ false, true) < 0) {
perror("failed to prepare workload");
return -1;
}
@@ -584,6 +596,14 @@
clock_gettime(CLOCK_MONOTONIC, &ref_time);
if (forks) {
+ /*
+ * perf_evlist__prepare_workload will, after we call
+ * perf_evlist__start_Workload, send a SIGUSR1 if the exec call
+ * fails, that we will catch in workload_signal to flip
+ * workload_exec_failed.
+ */
+ signal(SIGUSR1, workload_exec_failed_signal);
+
perf_evlist__start_workload(evsel_list);
handle_initial_delay();
@@ -594,6 +614,10 @@
}
}
wait(&status);
+
+ if (workload_exec_failed)
+ return -1;
+
if (WIFSIGNALED(status))
psignal(WTERMSIG(status), argv[0]);
} else {