diff mbox series

[1/4] perf pmu: Add function to check if a pmu file exists

Message ID 20220504150216.581281-2-german.gomez@arm.com (mailing list archive)
State New, archived
Headers show
Series perf cs_etm: Basic support for virtual/kernel timestamps | expand

Commit Message

German Gomez May 4, 2022, 3:02 p.m. UTC 
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>
---
 tools/perf/util/pmu.c | 17 +++++++++++++++++
 tools/perf/util/pmu.h |  2 ++
 2 files changed, 19 insertions(+)

Comments

Arnaldo Carvalho de Melo May 10, 2022, 4:41 p.m. UTC | #1 
Em Wed, May 04, 2022 at 04:02:12PM +0100, German Gomez escreveu:
> Add a utility function perf_pmu__file_exists() to check if a given pmu
> file exists in the sysfs filesystem.

While reviewing this I noticed:

int perf_pmu__caps_parse(struct perf_pmu *pmu)
{
        struct stat st;
        char caps_path[PATH_MAX];
        const char *sysfs = sysfs__mountpoint();
        DIR *caps_dir;
        struct dirent *evt_ent;
        int nr_caps = 0;

        if (!sysfs)
                return -1;

        snprintf(caps_path, PATH_MAX,
                 "%s" EVENT_SOURCE_DEVICE_PATH "%s/caps", sysfs, pmu->name);

        if (stat(caps_path, &st) < 0)
                return 0;       /* no error if caps does not exist */


------------------------

Shouldn't we introduce a:

const int perf__pmu_pathname_scnprintf(struct perf_pmu *pmu, char *pathname, size_t size, char *filename)
{

	return scnprintf(pathname, size, "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, filename);
}

And use in your perf_pmu__file_exists() and in the other places where
this open coded pattern appears?

I'm waiting for reviews for the ARM specific bits.

- Arnaldo
 
> Signed-off-by: German Gomez <german.gomez@arm.com>
> ---
>  tools/perf/util/pmu.c | 17 +++++++++++++++++
>  tools/perf/util/pmu.h |  2 ++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 9a1c7e63e663..9479e9a4da54 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -1854,6 +1854,23 @@ 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;
> +	const char *sysfs = sysfs__mountpoint();
> +
> +	if (!sysfs)
> +		return false;
> +
> +	snprintf(path, PATH_MAX,
> +		 "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, name);
> +	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 541889fa9f9c..ab728eaf13b6 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -120,6 +120,8 @@ 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
German Gomez May 11, 2022, 11:49 a.m. UTC | #2 
Hi Arnaldo, thanks for the review

On 10/05/2022 17:41, Arnaldo Carvalho de Melo wrote:
> Em Wed, May 04, 2022 at 04:02:12PM +0100, German Gomez escreveu:
>> Add a utility function perf_pmu__file_exists() to check if a given pmu
>> file exists in the sysfs filesystem.
> While reviewing this I noticed:
>
> int perf_pmu__caps_parse(struct perf_pmu *pmu)
> {
>         struct stat st;
>         char caps_path[PATH_MAX];
>         const char *sysfs = sysfs__mountpoint();
>         DIR *caps_dir;
>         struct dirent *evt_ent;
>         int nr_caps = 0;
>
>         if (!sysfs)
>                 return -1;
>
>         snprintf(caps_path, PATH_MAX,
>                  "%s" EVENT_SOURCE_DEVICE_PATH "%s/caps", sysfs, pmu->name);
>
>         if (stat(caps_path, &st) < 0)
>                 return 0;       /* no error if caps does not exist */
>
>
> ------------------------
>
> Shouldn't we introduce a:
>
> const int perf__pmu_pathname_scnprintf(struct perf_pmu *pmu, char *pathname, size_t size, char *filename)
> {
>
> 	return scnprintf(pathname, size, "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, filename);
> }
>
> And use in your perf_pmu__file_exists() and in the other places where
> this open coded pattern appears?

I agree. If nobody else has done it before me, I will send the refactor
in the next respin.

Thanks,
German

>
> I'm waiting for reviews for the ARM specific bits.
>
> - Arnaldo
>  
>> Signed-off-by: German Gomez <german.gomez@arm.com>
>> ---
>>  tools/perf/util/pmu.c | 17 +++++++++++++++++
>>  tools/perf/util/pmu.h |  2 ++
>>  2 files changed, 19 insertions(+)
>>
>> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
>> index 9a1c7e63e663..9479e9a4da54 100644
>> --- a/tools/perf/util/pmu.c
>> +++ b/tools/perf/util/pmu.c
>> @@ -1854,6 +1854,23 @@ 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;
>> +	const char *sysfs = sysfs__mountpoint();
>> +
>> +	if (!sysfs)
>> +		return false;
>> +
>> +	snprintf(path, PATH_MAX,
>> +		 "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, name);
>> +	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 541889fa9f9c..ab728eaf13b6 100644
>> --- a/tools/perf/util/pmu.h
>> +++ b/tools/perf/util/pmu.h
>> @@ -120,6 +120,8 @@ 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
diff mbox series

Patch

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 9a1c7e63e663..9479e9a4da54 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -1854,6 +1854,23 @@  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;
+	const char *sysfs = sysfs__mountpoint();
+
+	if (!sysfs)
+		return false;
+
+	snprintf(path, PATH_MAX,
+		 "%s" EVENT_SOURCE_DEVICE_PATH "%s/%s", sysfs, pmu->name, name);
+	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 541889fa9f9c..ab728eaf13b6 100644
--- a/tools/perf/util/pmu.h
+++ b/tools/perf/util/pmu.h
@@ -120,6 +120,8 @@  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);