[igt-dev] [RFC i-g-t 3/6] intel-gpu-overlay: Show 1s, 30s and 15m GPU load

[Tvrtko Ursulin <tursulin@ursulin.net>]

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Show total GPU loads in the window banner.

Engine load is defined as total of runnable and running requests on an
engine.

Total, non-normalized, load is display. In other words if N engines are
busy with exactly one request, the load will be shown as N.

v2:
 * Different flavour of load avg. (Chris Wilson)
 * Simplify code. (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 overlay/gpu-top.c | 39 ++++++++++++++++++++++++++++++++++++++-
 overlay/gpu-top.h | 11 ++++++++++-
 overlay/overlay.c | 28 ++++++++++++++++++++++------
 3 files changed, 70 insertions(+), 8 deletions(-)

diff --git a/overlay/gpu-top.c b/overlay/gpu-top.c
index 22e9badb22c1..501429b86379 100644
--- a/overlay/gpu-top.c
+++ b/overlay/gpu-top.c
@@ -28,6 +28,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <math.h>
 #include <errno.h>
 #include <assert.h>
 
@@ -126,6 +127,10 @@ static int perf_init(struct gpu_top *gt)
 		gt->ring[gt->num_rings++].name = d->name;
 	}
 
+	gt->have_load_avg = gt->have_queued &&
+			    gt->have_runnable &&
+			    gt->have_running;
+
 	return 0;
 }
 
@@ -290,17 +295,32 @@ static void mmio_init(struct gpu_top *gt)
 	}
 }
 
-void gpu_top_init(struct gpu_top *gt)
+void gpu_top_init(struct gpu_top *gt, unsigned int period_us)
 {
+	const double period = (double)period_us / 1e6;
+	const double load_period[NUM_LOADS] = { 1.0, 30.0, 900.0 };
+	const char *load_names[NUM_LOADS] = { "1s", "30s", "15m" };
+	unsigned int i;
+
 	memset(gt, 0, sizeof(*gt));
 	gt->fd = -1;
 
+	for (i = 0; i < NUM_LOADS; i++) {
+		gt->load_name[i] = load_names[i];
+		gt->exp[i] = exp(-period / load_period[i]);
+	}
+
 	if (perf_init(gt) == 0)
 		return;
 
 	mmio_init(gt);
 }
 
+static double update_load(double load, double exp, double val)
+{
+	return val + exp * (load - val);
+}
+
 int gpu_top_update(struct gpu_top *gt)
 {
 	uint32_t data[1024];
@@ -313,6 +333,8 @@ int gpu_top_update(struct gpu_top *gt)
 		struct gpu_top_stat *s = &gt->stat[gt->count++&1];
 		struct gpu_top_stat *d = &gt->stat[gt->count&1];
 		uint64_t *sample, d_time;
+		double gpu_qd = 0.0;
+		unsigned int i;
 		int n, m;
 
 		len = read(gt->fd, data, sizeof(data));
@@ -341,6 +363,8 @@ int gpu_top_update(struct gpu_top *gt)
 
 		d_time = s->time - d->time;
 		for (n = 0; n < gt->num_rings; n++) {
+			double qd = 0.0;
+
 			gt->ring[n].u.u.busy = (100 * (s->busy[n] - d->busy[n]) + d_time/2) / d_time;
 			if (gt->have_wait)
 				gt->ring[n].u.u.wait = (100 * (s->wait[n] - d->wait[n]) + d_time/2) / d_time;
@@ -353,6 +377,14 @@ int gpu_top_update(struct gpu_top *gt)
 			if (gt->have_running)
 				gt->ring[n].running = (double)((s->running[n] - d->running[n])) / I915_SAMPLE_RUNNING_DIVISOR * 1e9 / d_time;
 
+			qd = gt->ring[n].runnable + gt->ring[n].running;
+			gpu_qd += qd;
+
+			for (i = 0; i < NUM_LOADS; i++)
+				gt->ring[n].load[i] =
+					update_load(gt->ring[n].load[i],
+						    gt->exp[i], qd);
+
 			/* in case of rounding + sampling errors, fudge */
 			if (gt->ring[n].u.u.busy > 100)
 				gt->ring[n].u.u.busy = 100;
@@ -362,6 +394,11 @@ int gpu_top_update(struct gpu_top *gt)
 				gt->ring[n].u.u.sema = 100;
 		}
 
+		for (i = 0; i < NUM_LOADS; i++) {
+			gt->load[i] = update_load(gt->load[i], gt->exp[i],
+						  gpu_qd);
+			gt->norm_load[i] = gt->load[i] / gt->num_rings;
+		}
 		update = 1;
 	} else {
 		while ((len = read(gt->fd, data, sizeof(data))) > 0) {
diff --git a/overlay/gpu-top.h b/overlay/gpu-top.h
index cb4310c82a94..115ce8c482c1 100644
--- a/overlay/gpu-top.h
+++ b/overlay/gpu-top.h
@@ -26,6 +26,7 @@
 #define GPU_TOP_H
 
 #define MAX_RINGS 16
+#define NUM_LOADS 3
 
 #include <stdint.h>
 
@@ -39,6 +40,12 @@ struct gpu_top {
 	int have_queued;
 	int have_runnable;
 	int have_running;
+	int have_load_avg;
+
+	double exp[NUM_LOADS];
+	double load[NUM_LOADS];
+	double norm_load[NUM_LOADS];
+	const char *load_name[NUM_LOADS];
 
 	struct gpu_top_ring {
 		const char *name;
@@ -54,6 +61,8 @@ struct gpu_top {
 		double queued;
 		double runnable;
 		double running;
+
+		double load[NUM_LOADS];
 	} ring[MAX_RINGS];
 
 	struct gpu_top_stat {
@@ -69,7 +78,7 @@ struct gpu_top {
 	int count;
 };
 
-void gpu_top_init(struct gpu_top *gt);
+void gpu_top_init(struct gpu_top *gt, unsigned int period_us);
 int gpu_top_update(struct gpu_top *gt);
 
 #endif /* GPU_TOP_H */
diff --git a/overlay/overlay.c b/overlay/overlay.c
index 7087d5e5b24e..1a1d01db082b 100644
--- a/overlay/overlay.c
+++ b/overlay/overlay.c
@@ -141,7 +141,8 @@ struct overlay_context {
 };
 
 static void init_gpu_top(struct overlay_context *ctx,
-			 struct overlay_gpu_top *gt)
+			 struct overlay_gpu_top *gt,
+			 unsigned int period_us)
 {
 	const double rgba[][4] = {
 		{ 1, 0.25, 0.25, 1 },
@@ -153,7 +154,7 @@ static void init_gpu_top(struct overlay_context *ctx,
 	int n;
 
 	cpu_top_init(&gt->cpu_top);
-	gpu_top_init(&gt->gpu_top);
+	gpu_top_init(&gt->gpu_top, period_us);
 
 	chart_init(&gt->cpu, "CPU", 120);
 	chart_set_position(&gt->cpu, PAD, PAD);
@@ -928,13 +929,13 @@ int main(int argc, char **argv)
 
 	debugfs_init();
 
-	init_gpu_top(&ctx, &ctx.gpu_top);
+	sample_period = get_sample_period(&config);
+
+	init_gpu_top(&ctx, &ctx.gpu_top, sample_period);
 	init_gpu_perf(&ctx, &ctx.gpu_perf);
 	init_gpu_freq(&ctx, &ctx.gpu_freq);
 	init_gem_objects(&ctx, &ctx.gem_objects);
 
-	sample_period = get_sample_period(&config);
-
 	i = 0;
 	while (1) {
 		ctx.time = time(NULL);
@@ -950,9 +951,24 @@ int main(int argc, char **argv)
 		show_gem_objects(&ctx, &ctx.gem_objects);
 
 		{
-			char buf[80];
+			struct gpu_top *gt = &ctx.gpu_top.gpu_top;
 			cairo_text_extents_t extents;
+			char buf[256];
+
 			gethostname(buf, sizeof(buf));
+
+			if (gt->have_load_avg) {
+				int len = strlen(buf);
+
+				snprintf(buf + len, sizeof(buf) - len,
+					 "%s; %u engines; load %s %.2f, %s %.2f, %s %.2f",
+					 buf,
+					 gt->num_rings,
+					 gt->load_name[0], gt->load[0],
+					 gt->load_name[1], gt->load[1],
+					 gt->load_name[2], gt->load[2]);
+			}
+
 			cairo_set_source_rgb(ctx.cr, .5, .5, .5);
 			cairo_set_font_size(ctx.cr, PAD-2);
 			cairo_text_extents(ctx.cr, buf, &extents);
-- 
2.17.1

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