| Message ID | 20221222160328.3639989-5-james.clark@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf cs_etm: Basic support for virtual/kernel timestamps | expand |
On Thu, Dec 22, 2022 at 04:03:24PM +0000, James Clark wrote: > From: German Gomez <german.gomez@arm.com> > > Add a utility function perf_pmu__file_exists() to check if a given pmu > file exists in the sysfs filesystem. > > Signed-off-by: German Gomez <german.gomez@arm.com> > Signed-off-by: James Clark <james.clark@arm.com> > --- > tools/perf/util/pmu.c | 14 ++++++++++++++ > tools/perf/util/pmu.h | 2 ++ > 2 files changed, 16 insertions(+) > > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c > index 15b852b3c401..b72b2d892949 100644 > --- a/tools/perf/util/pmu.c > +++ b/tools/perf/util/pmu.c > @@ -1739,6 +1739,20 @@ int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt, > return ret; > } > > +bool perf_pmu__file_exists(struct perf_pmu *pmu, const char *name) > +{ > + char path[PATH_MAX]; > + struct stat statbuf; > + > + if (!perf_pmu__pathname_scnprintf(path, PATH_MAX, pmu->name, name)) > + return false; > + > + if (!file_available(path)) > + return false; > + > + return stat(path, &statbuf) == 0; Can we simply return the returned value from file_available() and skip calling stat()? Because file_available() invokes access() to detect if a file is existed or not, so here calling stat() is redundant. Thanks, Leo > +} > + > static int perf_pmu__new_caps(struct list_head *list, char *name, char *value) > { > struct perf_pmu_caps *caps = zalloc(sizeof(*caps)); > diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h > index 8f39e2d17fb1..c1d138fe9602 100644 > --- a/tools/perf/util/pmu.h > +++ b/tools/perf/util/pmu.h > @@ -230,6 +230,8 @@ bool pmu_have_event(const char *pname, const char *name); > > int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt, ...) __scanf(3, 4); > > +bool perf_pmu__file_exists(struct perf_pmu *pmu, const char *name); > + > int perf_pmu__test(void); > > struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu); > -- > 2.25.1 >
On 23/12/2022 06:26, Leo Yan wrote: > On Thu, Dec 22, 2022 at 04:03:24PM +0000, James Clark wrote: >> From: German Gomez <german.gomez@arm.com> >> >> Add a utility function perf_pmu__file_exists() to check if a given pmu >> file exists in the sysfs filesystem. >> >> Signed-off-by: German Gomez <german.gomez@arm.com> >> Signed-off-by: James Clark <james.clark@arm.com> >> --- >> tools/perf/util/pmu.c | 14 ++++++++++++++ >> tools/perf/util/pmu.h | 2 ++ >> 2 files changed, 16 insertions(+) >> >> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c >> index 15b852b3c401..b72b2d892949 100644 >> --- a/tools/perf/util/pmu.c >> +++ b/tools/perf/util/pmu.c >> @@ -1739,6 +1739,20 @@ int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt, >> return ret; >> } >> >> +bool perf_pmu__file_exists(struct perf_pmu *pmu, const char *name) >> +{ >> + char path[PATH_MAX]; >> + struct stat statbuf; >> + >> + if (!perf_pmu__pathname_scnprintf(path, PATH_MAX, pmu->name, name)) >> + return false; >> + >> + if (!file_available(path)) >> + return false; >> + >> + return stat(path, &statbuf) == 0; > > Can we simply return the returned value from file_available() and skip > calling stat()? Because file_available() invokes access() to detect if > a file is existed or not, so here calling stat() is redundant. > Yep that works. Fixed in V3.
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 15b852b3c401..b72b2d892949 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -1739,6 +1739,20 @@ int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt, return ret; } +bool perf_pmu__file_exists(struct perf_pmu *pmu, const char *name) +{ + char path[PATH_MAX]; + struct stat statbuf; + + if (!perf_pmu__pathname_scnprintf(path, PATH_MAX, pmu->name, name)) + return false; + + if (!file_available(path)) + return false; + + return stat(path, &statbuf) == 0; +} + static int perf_pmu__new_caps(struct list_head *list, char *name, char *value) { struct perf_pmu_caps *caps = zalloc(sizeof(*caps)); diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h index 8f39e2d17fb1..c1d138fe9602 100644 --- a/tools/perf/util/pmu.h +++ b/tools/perf/util/pmu.h @@ -230,6 +230,8 @@ bool pmu_have_event(const char *pname, const char *name); int perf_pmu__scan_file(struct perf_pmu *pmu, const char *name, const char *fmt, ...) __scanf(3, 4); +bool perf_pmu__file_exists(struct perf_pmu *pmu, const char *name); + int perf_pmu__test(void); struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu);