On Sat, Aug 02, 2014 at 07:58:25PM +0200, Yann Droneaud wrote:
> Hi Jiri,
SNIP
> > 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));
heh, I haven't realized that your probing event was
PERF_COUNT_SW_CPU_CLOCK, which could never be busy
and found following bug ;-)
jirka
---
We were using PERF_COUNT_SW_CPU_CLOCK as an probing event type.
Using expected PERF_TYPE_SOFTWARE type instead.
Cc: Adrian Hunter <adrian.hun...@intel.com>
Cc: Arnaldo Carvalho de Melo <a...@kernel.org>
Cc: David Ahern <dsah...@gmail.com>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Namhyung Kim <namhy...@gmail.com>
Cc: Paul Mackerras <pau...@samba.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Stephane Eranian <eran...@google.com>
Cc: William Cohen <wco...@redhat.com>
Cc: Yann Droneaud <ydrone...@opteya.com>
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
tools/perf/util/cloexec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
index dc360ebde745..0f7eb0a53d4b 100644
--- a/tools/perf/util/cloexec.c
+++ b/tools/perf/util/cloexec.c
@@ -9,7 +9,7 @@ static int perf_flag_probe(void)
{
/* use 'safest' configuration as used in perf_evsel__fallback() */
struct perf_event_attr attr = {
- .type = PERF_COUNT_SW_CPU_CLOCK,
+ .type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
};
int fd;
--
1.8.3.1
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