From: Andi Kleen <ak@linux.intel.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>,
acme@kernel.org, jolsa@kernel.org, eranian@google.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/7] perf pmu: Use file system cache to optimize sysfs access
Date: Mon, 28 Oct 2019 19:14:19 -0700 [thread overview]
Message-ID: <20191029021419.GT4660@tassilo.jf.intel.com> (raw)
In-Reply-To: <20191028220137.GF28772@krava>
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
next prev parent reply other threads:[~2019-10-29 2:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 18:14 Optimize perf stat for large number of events/cpus v3 Andi Kleen
2019-10-25 18:14 ` [PATCH v3 1/7] perf pmu: Use file system cache to optimize sysfs access Andi Kleen
2019-10-28 22:01 ` Jiri Olsa
2019-10-29 2:14 ` Andi Kleen [this message]
2019-10-25 18:14 ` [PATCH v3 2/7] perf affinity: Add infrastructure to save/restore affinity Andi Kleen
2019-10-25 18:14 ` [PATCH v3 3/7] perf evsel: Add iterator to iterate over events ordered by CPU Andi Kleen
2019-10-30 10:05 ` Jiri Olsa
2019-10-30 10:06 ` Jiri Olsa
2019-10-30 15:51 ` Andi Kleen
2019-10-30 18:15 ` Jiri Olsa
2019-10-30 19:03 ` Andi Kleen
2019-11-01 8:38 ` Jiri Olsa
2019-10-25 18:14 ` [PATCH v3 4/7] perf stat: Use affinity for closing file descriptors Andi Kleen
2019-10-30 10:05 ` Jiri Olsa
2019-11-04 23:35 ` Andi Kleen
2019-10-25 18:14 ` [PATCH v3 5/7] perf stat: Use affinity for opening events Andi Kleen
2019-10-30 10:06 ` Jiri Olsa
2019-10-25 18:14 ` [PATCH v3 6/7] perf stat: Use affinity for reading Andi Kleen
2019-10-25 18:14 ` [PATCH v3 7/7] perf stat: Use affinity for enabling/disabling events Andi Kleen
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