[PATCH v7 1/2] perf record: Propagate exit status of a command line workload

From: Namhyung Kim
Date: Sun May 11 2014 - 20:47:55 EST


Currently perf record doesn't propagate the exit status of a workload
given by the command line. But sometimes it'd useful if it's
propagated so that a monitoring script can handle errors
appropriately.

To do that, it moves most of logic out of the exit handlers and run
them directly in the __cmd_record(). The only thing needs to be done
in the handler is propagating terminating signal so that the shell can
terminate its loop properly when Ctrl-C was pressed. Also it cleaned
up the resource management code in record__exit().

With this change, perf record returns the child exit status in case of
normal termination and send signal to itself when terminated by signal.

Example run of Stephane's case:

$ perf record true && echo yes || echo no
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.013 MB perf.data (~589 samples) ]
yes

$ perf record false && echo yes || echo no
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.013 MB perf.data (~589 samples) ]
no

Jiri's case (error in parent):

$ perf record -m 10G true && echo yes || echo no
rounding mmap pages size to 17179869184 bytes (4194304 pages)
failed to mmap with 12 (Cannot allocate memory)
no

$ ulimit -n 6
$ perf record sleep 1 && echo yes || echo no
failed to create 'go' pipe: Too many open files
Couldn't run the workload!
no

And Peter's case (interrupted by signal):

$ while :; do perf record sleep 1; done
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.014 MB perf.data (~593 samples) ]

Reported-by: Stephane Eranian <eranian@xxxxxxxxxx>
Acked-by: Stephane Eranian <eranian@xxxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/builtin-record.c | 127 +++++++++++++++++++++-----------------------
1 file changed, 60 insertions(+), 67 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 8ce62ef7f6c3..2e0d484068d2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -147,29 +147,19 @@ static void sig_handler(int sig)
{
if (sig == SIGCHLD)
child_finished = 1;
+ else
+ signr = sig;

done = 1;
- signr = sig;
}

-static void record__sig_exit(int exit_status __maybe_unused, void *arg)
+static void record__sig_exit(void)
{
- struct record *rec = arg;
- int status;
-
- if (rec->evlist->workload.pid > 0) {
- if (!child_finished)
- kill(rec->evlist->workload.pid, SIGTERM);
-
- wait(&status);
- if (WIFSIGNALED(status))
- psignal(WTERMSIG(status), rec->progname);
- }
-
- if (signr == -1 || signr == SIGUSR1)
+ if (signr == -1)
return;

signal(signr, SIG_DFL);
+ raise(signr);
}

static int record__open(struct record *rec)
@@ -243,27 +233,6 @@ static int process_buildids(struct record *rec)
size, &build_id__mark_dso_hit_ops);
}

-static void record__exit(int status, void *arg)
-{
- struct record *rec = arg;
- struct perf_data_file *file = &rec->file;
-
- if (status != 0)
- return;
-
- if (!file->is_pipe) {
- rec->session->header.data_size += rec->bytes_written;
-
- if (!rec->no_buildid)
- process_buildids(rec);
- perf_session__write_header(rec->session, rec->evlist,
- file->fd, true);
- perf_session__delete(rec->session);
- perf_evlist__delete(rec->evlist);
- symbol__exit();
- }
-}
-
static void perf_event__synthesize_guest_os(struct machine *machine, void *data)
{
int err;
@@ -344,18 +313,19 @@ static volatile int workload_exec_errno;
* if the fork fails, since we asked by setting its
* want_signal to true.
*/
-static void workload_exec_failed_signal(int signo, siginfo_t *info,
+static void workload_exec_failed_signal(int signo __maybe_unused,
+ siginfo_t *info,
void *ucontext __maybe_unused)
{
workload_exec_errno = info->si_value.sival_int;
done = 1;
- signr = signo;
child_finished = 1;
}

static int __cmd_record(struct record *rec, int argc, const char **argv)
{
int err;
+ int status = 0;
unsigned long waking = 0;
const bool forks = argc > 0;
struct machine *machine;
@@ -367,7 +337,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)

rec->progname = argv[0];

- on_exit(record__sig_exit, rec);
+ atexit(record__sig_exit);
signal(SIGCHLD, sig_handler);
signal(SIGINT, sig_handler);
signal(SIGTERM, sig_handler);
@@ -388,32 +358,28 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
workload_exec_failed_signal);
if (err < 0) {
pr_err("Couldn't run the workload!\n");
+ status = err;
goto out_delete_session;
}
}

if (record__open(rec) != 0) {
err = -1;
- goto out_delete_session;
+ goto out_child;
}

if (!rec->evlist->nr_groups)
perf_header__clear_feat(&session->header, HEADER_GROUP_DESC);

- /*
- * perf_session__delete(session) will be called at record__exit()
- */
- on_exit(record__exit, rec);
-
if (file->is_pipe) {
err = perf_header__write_pipe(file->fd);
if (err < 0)
- goto out_delete_session;
+ goto out_child;
} else {
err = perf_session__write_header(session, rec->evlist,
file->fd, false);
if (err < 0)
- goto out_delete_session;
+ goto out_child;
}

if (!rec->no_buildid
@@ -421,7 +387,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
pr_err("Couldn't generate buildids. "
"Use --no-buildid to profile anyway.\n");
err = -1;
- goto out_delete_session;
+ goto out_child;
}

machine = &session->machines.host;
@@ -431,7 +397,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
process_synthesized_event);
if (err < 0) {
pr_err("Couldn't synthesize attrs.\n");
- goto out_delete_session;
+ goto out_child;
}

if (have_tracepoints(&rec->evlist->entries)) {
@@ -447,7 +413,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
process_synthesized_event);
if (err <= 0) {
pr_err("Couldn't record tracing data.\n");
- goto out_delete_session;
+ goto out_child;
}
rec->bytes_written += err;
}
@@ -475,7 +441,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->threads,
process_synthesized_event, opts->sample_address);
if (err != 0)
- goto out_delete_session;
+ goto out_child;

if (rec->realtime_prio) {
struct sched_param param;
@@ -484,7 +450,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
if (sched_setscheduler(0, SCHED_FIFO, &param)) {
pr_err("Could not set realtime priority.\n");
err = -1;
- goto out_delete_session;
+ goto out_child;
}
}

@@ -512,13 +478,15 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)

if (record__mmap_read_all(rec) < 0) {
err = -1;
- goto out_delete_session;
+ goto out_child;
}

if (hits == rec->samples) {
if (done)
break;
err = poll(rec->evlist->pollfd, rec->evlist->nr_fds, -1);
+ if (err < 0 && errno == EINTR)
+ err = 0;
waking++;
}

@@ -538,28 +506,52 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
const char *emsg = strerror_r(workload_exec_errno, msg, sizeof(msg));
pr_err("Workload failed: %s\n", emsg);
err = -1;
- goto out_delete_session;
+ goto out_child;
}

- if (quiet || signr == SIGUSR1)
- return 0;
+ if (!quiet) {
+ fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);

- fprintf(stderr, "[ perf record: Woken up %ld times to write data ]\n", waking);
+ /*
+ * Approximate RIP event size: 24 bytes.
+ */
+ fprintf(stderr,
+ "[ perf record: Captured and wrote %.3f MB %s (~%" PRIu64 " samples) ]\n",
+ (double)rec->bytes_written / 1024.0 / 1024.0,
+ file->path,
+ rec->bytes_written / 24);
+ }

- /*
- * Approximate RIP event size: 24 bytes.
- */
- fprintf(stderr,
- "[ perf record: Captured and wrote %.3f MB %s (~%" PRIu64 " samples) ]\n",
- (double)rec->bytes_written / 1024.0 / 1024.0,
- file->path,
- rec->bytes_written / 24);
+out_child:
+ if (forks) {
+ int exit_status;

- return 0;
+ if (!child_finished)
+ kill(rec->evlist->workload.pid, SIGTERM);
+
+ wait(&exit_status);
+
+ if (err < 0)
+ status = err;
+ else if (WIFEXITED(exit_status))
+ status = WEXITSTATUS(exit_status);
+ else if (WIFSIGNALED(exit_status))
+ signr = WTERMSIG(exit_status);
+ } else
+ status = err;
+
+ if (!err && !file->is_pipe) {
+ rec->session->header.data_size += rec->bytes_written;
+
+ if (!rec->no_buildid)
+ process_buildids(rec);
+ perf_session__write_header(rec->session, rec->evlist,
+ file->fd, true);
+ }

out_delete_session:
perf_session__delete(session);
- return err;
+ return status;
}

#define BRANCH_OPT(n, m) \
@@ -988,6 +980,7 @@ int cmd_record(int argc, const char **argv, const char *prefix __maybe_unused)

err = __cmd_record(&record, argc, argv);
out_symbol_exit:
+ perf_evlist__delete(rec->evlist);
symbol__exit();
return err;
}
--
1.9.2

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