On Mon, Jan 27, 2025 at 02:33:00PM -0800, Vinay Belgaumkar wrote:
Functions to parse event ID and GT bit shift for PMU events.
v2: Review comments (Riana)
Cc: Riana Tauro <riana.tauro@xxxxxxxxx>
Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
Cc: Kamil Konieczny <kamil.konieczny@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@xxxxxxxxx>
---
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..7e81d5516 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: Device string in driver:pci format
driver:pci seems wrong and is not true neither for i915 or xe.
This is actually the pmu_device:
/sys/bus/event_source/devices/{pmu_device}/events/{event_name}
and
/sys/bus/event_source/devices/{pmu_device}/format/{field}
+ * @param: Parameter for which you need the format start/end bits
+ * Returns: Start/end bit positions for a event parameter format
Returns 0 on success, or a negative error code on failure.
would be more accurate to the int return of this function
+ */
+int perf_event_format(const char *device, const char *param, uint32_t *start, uint32_t *end)
+{
+ char buf[NAME_MAX];
it seems this was part of a previous review, but I don't understand how
NAME_MAX is related to the buffer size here. You use it for the entire
**path** size and then re-use it for the buffer content.
Well... don´t really care much: as long as we don't overflow and when we
do we fail accordingly, should be good enough **for IGT**
+ 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
we have igt_sysfs_read() that could be used here (note dirfd is ignored
when path is absolute).
not really blocking this as is though.
Lucas De Marchi
+ 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 */
--
2.38.1
