Messages in this thread | | | Date | Mon, 28 Oct 2019 19:14:19 -0700 | From | Andi Kleen <> | Subject | Re: [PATCH v3 1/7] perf pmu: Use file system cache to optimize sysfs access |
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On Mon, Oct 28, 2019 at 11:01:37PM +0100, Jiri Olsa wrote: > On Fri, Oct 25, 2019 at 11:14:11AM -0700, Andi Kleen wrote: > > SNIP > > > if (pmu_aliases_parse(path, head)) > > return -1; > > @@ -525,7 +524,6 @@ static int pmu_alias_terms(struct perf_pmu_alias *alias, > > */ > > static int pmu_type(const char *name, __u32 *type) > > { > > - struct stat st; > > char path[PATH_MAX]; > > FILE *file; > > int ret = 0; > > @@ -537,7 +535,7 @@ static int pmu_type(const char *name, __u32 *type) > > snprintf(path, PATH_MAX, > > "%s" EVENT_SOURCE_DEVICE_PATH "%s/type", sysfs, name); > > > > - if (stat(path, &st) < 0) > > + if (access(path, R_OK) < 0) > > why not file_available call in here?
iirc it doesn't do any redundant accesses.
-Andi
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