* [PATCH 1/2] perf evlist: Add a method to return the list of evsels as a string
2021-04-14 13:16 [RFC] Improve workload error in 'perf record' Arnaldo Carvalho de Melo
@ 2021-04-14 13:16 ` Arnaldo Carvalho de Melo
2021-04-14 13:16 ` [PATCH 2/2] perf record: Improve 'Workload failed' message printing events + what was exec'ed Arnaldo Carvalho de Melo
2021-04-15 5:33 ` [RFC] Improve workload error in 'perf record' Ian Rogers
2 siblings, 0 replies; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-04-14 13:16 UTC (permalink / raw)
To: Jiri Olsa, Namhyung Kim
Cc: Ingo Molnar, Thomas Gleixner, Clark Williams, linux-kernel,
linux-perf-users, Arnaldo Carvalho de Melo, Adrian Hunter,
Ian Rogers
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Add a 'scnprintf' method to obtain the list of evsels in a evlist as a
string, excluding the "dummy" event used for things like receiving
metadata events (PERF_RECORD_FORK, MMAP, etc) when synthesizing
preexisting threads.
Will be used to improve the error message for workload failure in 'perf
record.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/evlist.c | 19 +++++++++++++++++++
tools/perf/util/evlist.h | 2 ++
2 files changed, 21 insertions(+)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index f1c79ecf81073f74..d29a8a118973c71c 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -2138,3 +2138,22 @@ struct evsel *evlist__find_evsel(struct evlist *evlist, int idx)
}
return NULL;
}
+
+int evlist__scnprintf_evsels(struct evlist *evlist, size_t size, char *bf)
+{
+ struct evsel *evsel;
+ int printed = 0;
+
+ evlist__for_each_entry(evlist, evsel) {
+ if (evsel__is_dummy_event(evsel))
+ continue;
+ if (size > (strlen(evsel__name(evsel)) + (printed ? 2 : 1))) {
+ printed += scnprintf(bf + printed, size - printed, "%s%s", printed ? "," : "", evsel__name(evsel));
+ } else {
+ printed += scnprintf(bf + printed, size - printed, "%s...", printed ? "," : "");
+ break;
+ }
+ }
+
+ return printed;
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index b695ffaae519a5d0..a8b97b50cceb7e43 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -365,4 +365,6 @@ int evlist__ctlfd_ack(struct evlist *evlist);
#define EVLIST_DISABLED_MSG "Events disabled\n"
struct evsel *evlist__find_evsel(struct evlist *evlist, int idx);
+
+int evlist__scnprintf_evsels(struct evlist *evlist, size_t size, char *bf);
#endif /* __PERF_EVLIST_H */
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 2/2] perf record: Improve 'Workload failed' message printing events + what was exec'ed
2021-04-14 13:16 [RFC] Improve workload error in 'perf record' Arnaldo Carvalho de Melo
2021-04-14 13:16 ` [PATCH 1/2] perf evlist: Add a method to return the list of evsels as a string Arnaldo Carvalho de Melo
@ 2021-04-14 13:16 ` Arnaldo Carvalho de Melo
2021-04-15 5:33 ` [RFC] Improve workload error in 'perf record' Ian Rogers
2 siblings, 0 replies; 4+ messages in thread
From: Arnaldo Carvalho de Melo @ 2021-04-14 13:16 UTC (permalink / raw)
To: Jiri Olsa, Namhyung Kim
Cc: Ingo Molnar, Thomas Gleixner, Clark Williams, linux-kernel,
linux-perf-users, Arnaldo Carvalho de Melo, Adrian Hunter,
Ian Rogers
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Before:
# perf record -a cycles,instructions,cache-misses
Workload failed: No such file or directory
#
After:
# perf record -a cycles,instructions,cache-misses
Failed to collect 'cycles' for the 'cycles,instructions,cache-misses' workload: No such file or directory
#
Helps disambiguating other error scenarios:
# perf record -a -e cycles,instructions,cache-misses bla
Failed to collect 'cycles,instructions,cache-misses' for the 'bla' workload: No such file or directory
# perf record -a cycles,instructions,cache-misses sleep 1
Failed to collect 'cycles' for the 'cycles,instructions,cache-misses' workload: No such file or directory
#
When all goes well we're back to the usual:
# perf record -a -e cycles,instructions,cache-misses sleep 1
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 3.151 MB perf.data (21242 samples) ]
#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-record.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 35465d1db6dda3ae..5fb9665a2ec27dde 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -1977,9 +1977,13 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
record__auxtrace_snapshot_exit(rec);
if (forks && workload_exec_errno) {
- char msg[STRERR_BUFSIZE];
+ char msg[STRERR_BUFSIZE], strevsels[2048];
const char *emsg = str_error_r(workload_exec_errno, msg, sizeof(msg));
- pr_err("Workload failed: %s\n", emsg);
+
+ evlist__scnprintf_evsels(rec->evlist, sizeof(strevsels), strevsels);
+
+ pr_err("Failed to collect '%s' for the '%s' workload: %s\n",
+ strevsels, argv[0], emsg);
err = -1;
goto out_child;
}
--
2.26.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [RFC] Improve workload error in 'perf record'
2021-04-14 13:16 [RFC] Improve workload error in 'perf record' Arnaldo Carvalho de Melo
2021-04-14 13:16 ` [PATCH 1/2] perf evlist: Add a method to return the list of evsels as a string Arnaldo Carvalho de Melo
2021-04-14 13:16 ` [PATCH 2/2] perf record: Improve 'Workload failed' message printing events + what was exec'ed Arnaldo Carvalho de Melo
@ 2021-04-15 5:33 ` Ian Rogers
2 siblings, 0 replies; 4+ messages in thread
From: Ian Rogers @ 2021-04-15 5:33 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Jiri Olsa, Namhyung Kim, Ingo Molnar, Thomas Gleixner,
Clark Williams, LKML, linux-perf-users, Adrian Hunter
On Wed, Apr 14, 2021 at 6:16 AM Arnaldo Carvalho de Melo
<acme@kernel.org> wrote:
>
> Hi,
>
> Please take a look,
>
> Best regards,
Acked-by: Ian Rogers <irogers@google.com>
Having been confused by this for a case in the past, thanks! It'd be
nice for code coverage's sake to have a shell test on this.
Thanks,
Ian
> - Arnaldo
>
> Arnaldo Carvalho de Melo (2):
> perf evlist: Add a method to return the list of evsels as a string
> perf record: Improve 'Workload failed' message printing events + what
> was exec'ed
>
> tools/perf/builtin-record.c | 8 ++++++--
> tools/perf/util/evlist.c | 19 +++++++++++++++++++
> tools/perf/util/evlist.h | 2 ++
> 3 files changed, 27 insertions(+), 2 deletions(-)
>
> --
> 2.26.2
>
^ permalink raw reply [flat|nested] 4+ messages in thread