Re: [igt-dev] [PATCH i-g-t v6 23/36] tools/i915-perf-recorder: capture OA & CS frequencies

[Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>]

On Mon, Oct 10, 2022 at 09:42:02PM +0000, Umesh Nerlige Ramappa wrote:
>From: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
>
>CS & OA timestamp don't have the same accuracy, so we need to adjuste
>the correlated timestamps (capture from the CS unit) in the recording
>to fit the data in the OA reports.
>
>Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

lgtm,

Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>

>---
> tools/i915-perf/i915_perf_recorder.c | 43 ++++++++++++++++++++++++----
> 1 file changed, 38 insertions(+), 5 deletions(-)
>
>diff --git a/tools/i915-perf/i915_perf_recorder.c b/tools/i915-perf/i915_perf_recorder.c
>index 7ced7b40..72011c87 100644
>--- a/tools/i915-perf/i915_perf_recorder.c
>+++ b/tools/i915-perf/i915_perf_recorder.c
>@@ -328,7 +328,7 @@ perf_ioctl(int fd, unsigned long request, void *arg)
> }
>
> static uint64_t
>-get_device_timestamp_frequency(const struct intel_device_info *devinfo, int drm_fd)
>+get_device_cs_timestamp_frequency(const struct intel_device_info *devinfo, int drm_fd)
> {
> 	drm_i915_getparam_t gp;
> 	int timestamp_frequency;
>@@ -352,12 +352,44 @@ get_device_timestamp_frequency(const struct intel_device_info *devinfo, int drm_
> 	return 12000000;
> }
>
>+static uint64_t
>+get_device_oa_timestamp_frequency(const struct intel_device_info *devinfo, int drm_fd)
>+{
>+	drm_i915_getparam_t gp;
>+	int timestamp_frequency;
>+
>+	gp.param = I915_PARAM_OA_TIMESTAMP_FREQUENCY;
>+	gp.value = &timestamp_frequency;
>+	if (perf_ioctl(drm_fd, DRM_IOCTL_I915_GETPARAM, &gp) == 0)
>+		return timestamp_frequency;
>+
>+	gp.param = I915_PARAM_CS_TIMESTAMP_FREQUENCY;
>+	gp.value = &timestamp_frequency;
>+	if (perf_ioctl(drm_fd, DRM_IOCTL_I915_GETPARAM, &gp) == 0)
>+		return timestamp_frequency;
>+
>+
>+	if (devinfo->graphics_ver > 9) {
>+		fprintf(stderr, "Unable to query timestamp frequency from i915, please update kernel.\n");
>+		return 0;
>+	}
>+
>+	fprintf(stderr, "Warning: unable to query timestamp frequency from i915, guessing values...\n");
>+
>+	if (devinfo->graphics_ver <= 8)
>+		return 12500000;
>+	if (devinfo->is_broxton)
>+		return 19200000;
>+	return 12000000;
>+}
>+
> struct recording_context {
> 	int drm_fd;
> 	int perf_fd;
>
> 	uint32_t devid;
>-	uint64_t timestamp_frequency;
>+	uint64_t oa_timestamp_frequency;
>+	uint64_t cs_timestamp_frequency;
>
> 	const struct intel_device_info *devinfo;
>
>@@ -459,7 +491,7 @@ static bool
> write_header(FILE *output, struct recording_context *ctx)
> {
> 	struct intel_perf_record_device_info info = {
>-		.timestamp_frequency = ctx->timestamp_frequency,
>+		.timestamp_frequency = ctx->oa_timestamp_frequency,
> 		.device_id = ctx->perf->devinfo.devid,
> 		.device_revision = ctx->perf->devinfo.revision,
> 		.gt_min_frequency = ctx->perf->devinfo.gt_min_freq,
>@@ -964,7 +996,8 @@ main(int argc, char *argv[])
>
> 	intel_perf_load_perf_configs(ctx.perf, ctx.drm_fd);
>
>-	ctx.timestamp_frequency = get_device_timestamp_frequency(ctx.devinfo, ctx.drm_fd);
>+	ctx.oa_timestamp_frequency = get_device_oa_timestamp_frequency(ctx.devinfo, ctx.drm_fd);
>+	ctx.cs_timestamp_frequency = get_device_cs_timestamp_frequency(ctx.devinfo, ctx.drm_fd);
>
> 	signal(SIGINT, sigint_handler);
>
>@@ -1036,7 +1069,7 @@ main(int argc, char *argv[])
> 		goto fail;
> 	}
>
>-	ctx.oa_exponent = oa_exponent_for_period(ctx.timestamp_frequency, perf_period);
>+	ctx.oa_exponent = oa_exponent_for_period(ctx.oa_timestamp_frequency, perf_period);
> 	fprintf(stdout, "Opening perf stream with metric_id=%"PRIu64" oa_exponent=%u oa_format=%u\n",
> 		ctx.metric_set->perf_oa_metrics_set, ctx.oa_exponent,
> 		ctx.metric_set->perf_oa_format);
>-- 
>2.25.1
>