[PATCH i-g-t v7 2/3] lib/igt_perf: Add utils to extract PMU event info

[Riana Tauro]

On 1/31/2025 3:00 AM, Vinay Belgaumkar wrote:
> Functions to parse event ID and GT bit shift for PMU events.
> 
> v2: Review comments (Riana)
> v3: Review comments (Lucas)
> 
> Cc: Riana Tauro <riana.tauro at intel.com>
> Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> Cc: Kamil Konieczny <kamil.konieczny at linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
Looks good to me

Reviewed-by: Riana Tauro <riana.tauro at intel.com>
> ---
>   lib/igt_perf.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
>   lib/igt_perf.h |  2 ++
>   2 files changed, 72 insertions(+)
> 
> diff --git a/lib/igt_perf.c b/lib/igt_perf.c
> index 3866c6d77..f021fc3ec 100644
> --- a/lib/igt_perf.c
> +++ b/lib/igt_perf.c
> @@ -92,6 +92,76 @@ const char *xe_perf_device(int xe, char *buf, int buflen)
>   	return buf;
>   }
>   
> +/**
> + * perf_event_format: Returns the start/end positions of an event format param
> + * @device: PMU device
> + * @param: Parameter for which you need the format start/end bits
> + * Returns: 0 on success or negative error code
> + */
> +int perf_event_format(const char *device, const char *param, uint32_t *start, uint32_t *end)
> +{
> +	char buf[NAME_MAX];
> +	ssize_t bytes;
> +	int ret;
> +	int fd;
> +
> +	snprintf(buf, sizeof(buf),
> +		 "/sys/bus/event_source/devices/%s/format/%s",
> +		 device, param);
> +
> +	fd = open(buf, O_RDONLY | O_CLOEXEC);
> +	if (fd < 0)
> +		return -EINVAL;
> +
> +	bytes = read(fd, buf, sizeof(buf) - 1);
> +	close(fd);
> +	if (bytes < 1)
> +		return -EINVAL;
> +
> +	buf[bytes] = '\0';
> +	ret = sscanf(buf, "config:%u-%u", start, end);
> +	if (ret != 2)
> +		return -EINVAL;
> +
> +	return ret;
> +}
> +
> +/**
> + * perf_event_config:
> + * @device: Device string in driver:pci format
> + * @event: The event name
> + * @config: Pointer to the config
> + * Returns: 0 for success, negative value on error
> + */
> +int perf_event_config(const char *device, const char *event, uint64_t *config)
> +{
> +	char buf[NAME_MAX];
> +	ssize_t bytes;
> +	int ret;
> +	int fd;
> +
> +	snprintf(buf, sizeof(buf),
> +		 "/sys/bus/event_source/devices/%s/events/%s",
> +		 device,
> +		 event);
> +
> +	fd = open(buf, O_RDONLY);
> +	if (fd < 0)
> +		return -EINVAL;
> +
> +	bytes = read(fd, buf, sizeof(buf) - 1);
> +	close(fd);
> +	if (bytes < 1)
> +		return ret;
> +
> +	buf[bytes] = '\0';
> +	ret = sscanf(buf, "event=0x%lx", config);
> +	if (ret != 1)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
>   uint64_t xe_perf_type_id(int xe)
>   {
>   	char buf[80];
> diff --git a/lib/igt_perf.h b/lib/igt_perf.h
> index 3d9ba2917..69f7a3d74 100644
> --- a/lib/igt_perf.h
> +++ b/lib/igt_perf.h
> @@ -71,5 +71,7 @@ int perf_i915_open(int i915, uint64_t config);
>   int perf_i915_open_group(int i915, uint64_t config, int group);
>   
>   int perf_xe_open(int xe, uint64_t config);
> +int perf_event_config(const char *device, const char *event, uint64_t *config);
> +int perf_event_format(const char *device, const char *param, uint32_t *start, uint32_t *end);
>   
>   #endif /* I915_PERF_H */