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Date: Wed, 23 Apr 2014 14:11:40 +0200
From: Stephane Eranian <eranian@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
Jiri Olsa <jolsa@...hat.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...nel.org>,
Paul Mackerras <paulus@...ba.org>,
Namhyung Kim <namhyung.kim@....com>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] perf record: Propagate exit status of a command
line workload
On Wed, Apr 23, 2014 at 8:40 AM, Namhyung Kim <namhyung@...nel.org> wrote:
> 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 got rid of exit handlers and run/call them directly in
> the __cmd_record(). I don't see any reason why those are in a form of
> exit handlers in the first place. Also it cleaned up the resouce
> management code in record__exit().
>
> With this change, perf record returns the child exit status in case of
> normal termination. (Not sure what should be returned on abnormal
> cases though).
>
> Example run of Stephane's case:
>
> $ 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
>
> And 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
>
> Reported-by: Stephane Eranian <eranian@...gle.com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
> tools/perf/builtin-record.c | 119 ++++++++++++++++++--------------------------
> 1 file changed, 49 insertions(+), 70 deletions(-)
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index eb524f91bffe..d315be9e9be2 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -152,26 +152,6 @@ static void sig_handler(int sig)
> signr = sig;
> }
>
> -static void record__sig_exit(int exit_status __maybe_unused, void *arg)
> -{
> - 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)
> - return;
> -
> - signal(signr, SIG_DFL);
> -}
> -
> static int record__open(struct record *rec)
> {
> char msg[512];
> @@ -243,27 +223,6 @@ 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;
> @@ -356,6 +315,7 @@ static void workload_exec_failed_signal(int signo, siginfo_t *info,
> 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 +327,6 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>
> rec->progname = argv[0];
>
> - on_exit(record__sig_exit, rec);
> signal(SIGCHLD, sig_handler);
> signal(SIGINT, sig_handler);
> signal(SIGTERM, sig_handler);
> @@ -394,26 +353,21 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>
> 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 +375,7 @@ 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 +385,7 @@ 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 +401,7 @@ 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 +429,7 @@ 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 +438,7 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
> if (sched_setscheduler(0, SCHED_FIFO, ¶m)) {
> pr_err("Could not set realtime priority.\n");
> err = -1;
> - goto out_delete_session;
> + goto out_child;
> }
> }
>
> @@ -512,7 +466,7 @@ 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) {
> @@ -538,28 +492,52 @@ 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)
Not quite this. Although this works with my test case with 'false'.
It fails when I tried the opposite test 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) ]
no
The return code in this case is 255. I tracked it down to err being last set
by poll() which got interrupted by SIGCHLD. So I think the err value must
be overridden somehow in this case. Maybe something like:
err = poll(evsel_list->pollfd, evsel_list->nr_fds, -1);
if (err < 0 && errno == EINTR && forks && done)
err = 0;
> + status = err;
> + else if (WIFEXITED(exit_status))
> + status = WEXITSTATUS(exit_status);
> + else if (WIFSIGNALED(status))
> + psignal(WTERMSIG(status), rec->progname);
> + } 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 +966,7 @@ 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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