scene_output: optionally record and report timings

examples/scene-graph.c

@@ -57,7 +57,7 @@ struct output {
 static void output_handle_frame(struct wl_listener *listener, void *data) {
 	struct output *output = wl_container_of(listener, output, frame);
 
-	if (!wlr_scene_output_commit(output->scene_output)) {
+	if (!wlr_scene_output_commit(output->scene_output, NULL)) {
 		return;
 	}
 

include/wlr/types/wlr_scene.h

@@ -209,6 +209,11 @@ struct wlr_scene_output {
 	struct wl_array render_list;
 };
 
+struct wlr_scene_timer {
+	int64_t pre_render_duration;
+	struct wlr_render_timer *render_timer;
+};
+
 /** A layer shell scene helper */
 struct wlr_scene_layer_surface_v1 {
 	struct wlr_scene_tree *tree;
@@ -455,16 +460,30 @@ void wlr_scene_output_destroy(struct wlr_scene_output *scene_output);
 void wlr_scene_output_set_position(struct wlr_scene_output *scene_output,
 	int lx, int ly);
 
+struct wlr_scene_output_state_options {
+	struct wlr_scene_timer *timer;
+};
+
 /**
  * Render and commit an output.
  */
-bool wlr_scene_output_commit(struct wlr_scene_output *scene_output);
+bool wlr_scene_output_commit(struct wlr_scene_output *scene_output,
+	const struct wlr_scene_output_state_options *options);
 
 /**
  * Render and populate given output state.
  */
 bool wlr_scene_output_build_state(struct wlr_scene_output *scene_output,
-	struct wlr_output_state *state);
+	struct wlr_output_state *state, const struct wlr_scene_output_state_options *options);
+
+/**
+ * Retrieve the duration in nanoseconds between the last wlr_scene_output_commit() call and the end
+ * of its operations, including those on the GPU that may have finished after the call returned.
+ *
+ * Returns -1 if the duration is unavailable.
+ */
+int64_t wlr_scene_timer_get_duration_ns(struct wlr_scene_timer *timer);
+void wlr_scene_timer_finish(struct wlr_scene_timer *timer);
 
 /**
  * Call wlr_surface_send_frame_done() on all surfaces in the scene rendered by

tinywl/tinywl.c

@@ -559,7 +559,7 @@ static void output_frame(struct wl_listener *listener, void *data) {
 		scene, output->wlr_output);
 
 	/* Render the scene if needed and commit the output */
-	wlr_scene_output_commit(scene_output);
+	wlr_scene_output_commit(scene_output, NULL);
 
 	struct timespec now;
 	clock_gettime(CLOCK_MONOTONIC, &now);

types/scene/wlr_scene.c

@@ -1584,7 +1584,8 @@ static bool scene_entry_try_direct_scanout(struct render_list_entry *entry,
 	return true;
 }
 
-bool wlr_scene_output_commit(struct wlr_scene_output *scene_output) {
+bool wlr_scene_output_commit(struct wlr_scene_output *scene_output,
+		const struct wlr_scene_output_state_options *options) {
 	if (!scene_output->output->needs_frame && !pixman_region32_not_empty(
 			&scene_output->damage_ring.current)) {
 		return true;
@@ -1593,7 +1594,7 @@ bool wlr_scene_output_commit(struct wlr_scene_output *scene_output) {
 	bool ok = false;
 	struct wlr_output_state state;
 	wlr_output_state_init(&state);
-	if (!wlr_scene_output_build_state(scene_output, &state)) {
+	if (!wlr_scene_output_build_state(scene_output, &state, options)) {
 		goto out;
 	}
 
@@ -1610,7 +1611,19 @@ out:
 }
 
 bool wlr_scene_output_build_state(struct wlr_scene_output *scene_output,
-		struct wlr_output_state *state) {
+		struct wlr_output_state *state, const struct wlr_scene_output_state_options *options) {
+	struct wlr_scene_output_state_options default_options = {0};
+	if (!options) {
+		options = &default_options;
+	}
+	struct wlr_scene_timer *timer = options->timer;
+	struct timespec start_time;
+	if (timer) {
+		clock_gettime(CLOCK_MONOTONIC, &start_time);
+		wlr_scene_timer_finish(timer);
+		*timer = (struct wlr_scene_timer){0};
+	}
+
 	if ((state->committed & WLR_OUTPUT_STATE_ENABLED) && !state->enabled) {
 		// if the state is being disabled, do nothing.
 		return true;
@@ -1683,6 +1696,12 @@ bool wlr_scene_output_build_state(struct wlr_scene_output *scene_output,
 	}
 
 	if (scanout) {
+		if (timer) {
+			struct timespec end_time, duration;
+			clock_gettime(CLOCK_MONOTONIC, &end_time);
+			timespec_sub(&duration, &end_time, &start_time);
+			timer->pre_render_duration = timespec_to_nsec(&duration);
+		}
 		return true;
 	}
 
@@ -1742,7 +1761,19 @@ bool wlr_scene_output_build_state(struct wlr_scene_output *scene_output,
 		return false;
 	}
 
-	struct wlr_render_pass *render_pass = wlr_renderer_begin_buffer_pass(output->renderer, buffer, NULL);
+	if (timer) {
+		timer->render_timer = wlr_render_timer_create(output->renderer);
+
+		struct timespec end_time, duration;
+		clock_gettime(CLOCK_MONOTONIC, &end_time);
+		timespec_sub(&duration, &end_time, &start_time);
+		timer->pre_render_duration = timespec_to_nsec(&duration);
+	}
+
+	struct wlr_render_pass *render_pass = wlr_renderer_begin_buffer_pass(output->renderer, buffer,
+			&(struct wlr_buffer_pass_options){
+		.timer = timer ? timer->render_timer : NULL,
+	});
 	if (render_pass == NULL) {
 		wlr_buffer_unlock(buffer);
 		return false;
@@ -1859,6 +1890,21 @@ bool wlr_scene_output_build_state(struct wlr_scene_output *scene_output,
 	return true;
 }
 
+int64_t wlr_scene_timer_get_duration_ns(struct wlr_scene_timer *timer) {
+	int64_t pre_render = timer->pre_render_duration;
+	if (!timer->render_timer) {
+		return pre_render;
+	}
+	int64_t render = wlr_render_timer_get_duration_ns(timer->render_timer);
+	return render != -1 ? pre_render + render : -1;
+}
+
+void wlr_scene_timer_finish(struct wlr_scene_timer *timer) {
+	if (timer->render_timer) {
+		wlr_render_timer_destroy(timer->render_timer);
+	}
+}
+
 static void scene_node_send_frame_done(struct wlr_scene_node *node,
 		struct wlr_scene_output *scene_output, struct timespec *now) {
 	if (!node->enabled) {