Hi Jiri,
Le vendredi 01 août 2014 à 17:46 +0200, Jiri Olsa a écrit :
> Showing better error message in case we fail to open
> counters due to the EBUSY error. If we detect oprofile
> daemon process running, we now display following message
> for EBUSY error:
>
> $ perf record ls
> Error:
> The PMU counters are busy/taken by another profiler.
> We found oprofile daemon running, please stop it and try again.
>
> In case oprofiled was not detected the current error
> message stays:
>
> $ perf record ls
> Error:
> The sys_perf_event_open() syscall returned with 16 (Device or resource
> busy) for event (cycles).
> /bin/dmesg may provide additional information.
> No CONFIG_PERF_EVENTS=y kernel support configured?
>
> Also changing PERF_FLAG_FD_CLOEXEC detection code not to display
> error in case of EBUSY error, as it currently does:
>
> $ perf record ls
> Error:
> perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error 16
> (Device or resource busy)
> perf_event_open(..., 0) failed unexpectedly with error 16 (Device or
> resource busy)
> The PMU counters are busy/taken by another profiler.
> We found oprofile daemon running, please stop it and try again.
>
> Cc: Adrian Hunter <[email protected]>
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Cc: David Ahern <[email protected]>
> Cc: Frederic Weisbecker <[email protected]>
> Cc: Namhyung Kim <[email protected]>
> Cc: Paul Mackerras <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Stephane Eranian <[email protected]>
> Cc: William Cohen <[email protected]>
> Cc: Yann Droneaud <[email protected]>
> Signed-off-by: Jiri Olsa <[email protected]>
> ---
> tools/perf/util/cloexec.c | 4 ++--
> tools/perf/util/evsel.c | 6 ++++++
> tools/perf/util/util.c | 36 ++++++++++++++++++++++++++++++++++++
> tools/perf/util/util.h | 1 +
> 4 files changed, 45 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
> index c5d05ec17220..dede0c388ed4 100644
> --- a/tools/perf/util/cloexec.c
> +++ b/tools/perf/util/cloexec.c
> @@ -25,7 +25,7 @@ static int perf_flag_probe(void)
> return 1;
> }
>
> - WARN_ONCE(err != EINVAL,
> + WARN_ONCE(err != EINVAL && err != EBUSY,
> "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with
> unexpected error %d (%s)\n",
> err, strerror(err));
>
> @@ -33,7 +33,7 @@ static int perf_flag_probe(void)
> fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
> err = errno;
>
> - if (WARN_ONCE(fd < 0,
> + if (WARN_ONCE(fd < 0 && err != EBUSY,
> "perf_event_open(..., 0) failed unexpectedly with error
> %d (%s)\n",
> err, strerror(err)))
> return -1;
It's definitely possible to shortcut the function if EBUSY is returned
by first call to perf_event_open().
diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
index dc360ebde745..d5c626d5432a 100644
--- a/tools/perf/util/cloexec.c
+++ b/tools/perf/util/cloexec.c
@@ -25,6 +25,9 @@ static int perf_flag_probe(void)
return 1;
}
+ if (err == EBUSY)
+ return -1;
+
WARN_ONCE(err != EINVAL,
"perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with
unexpected error %d (%s)\n",
err, strerror(err));
BTW, I'm going to submit a patch to make the function report such
warning only once.
Regards.
--
Yann Droneaud
OPTEYA
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