[PATCH weston 6/7] Switch to global output repaint hook

Daniel Stone daniels at collabora.com
Tue Feb 14 13:18:06 UTC 2017


In preparation for grouping output repaint together where possible,
switch the per-output repaint timer to a global timer which iterates
across all outputs.

This is implemented by storing the absolute time for the next repaint
for each output locally, and maintaining a global timer hook which
iterates all of them, scheduling the repaint for the first available
time.

Signed-off-by: Daniel Stone <daniels at collabora.com>
Cc: Mario Kleiner <mario.kleiner.de at gmail.com>
Cc: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
---
 libweston/compositor.c | 101 +++++++++++++++++++++++++++++++++++++------------
 libweston/compositor.h |   3 +-
 2 files changed, 79 insertions(+), 25 deletions(-)

diff --git a/libweston/compositor.c b/libweston/compositor.c
index ed8ef90fd..7ba6b45bf 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -2332,16 +2332,22 @@ weston_output_repaint(struct weston_output *output)
 static void
 weston_output_schedule_repaint_reset(struct weston_output *output)
 {
+	output->next_repaint = 0;
 	output->repaint_scheduled = 0;
 	TL_POINT("core_repaint_exit_loop", TLP_OUTPUT(output), TLP_END);
 }
 
-static int
-output_repaint_timer_handler(void *data)
+static void
+weston_output_maybe_repaint(struct weston_output *output,
+			    struct timespec *now)
 {
-	struct weston_output *output = data;
 	struct weston_compositor *compositor = output->compositor;
 	int ret;
+	uint32_t now_ms = timespec_to_msec(now);
+
+	/* We're not ready yet; come back to make a decision later. */
+	if (output->next_repaint == 0 || now_ms < output->next_repaint - 1)
+		return;
 
 	/* If we're sleeping, drop the repaint machinery entirely; we will
 	 * explicitly repaint all outputs when we come back. */
@@ -2354,17 +2360,65 @@ output_repaint_timer_handler(void *data)
 	if (!output->repaint_needed)
 		goto err;
 
+	output->next_repaint = 0;
+
 	/* If repaint fails, we aren't going to get weston_output_finish_frame
 	 * to trigger a new repaint, so drop it from repaint and hope
-	 * something schedules a successful repaint later. */
+	 * something schedules a successful repaint later. As repainting may
+	 * take some time, re-read our clock as a courtesy to the next
+	 * output. */
 	ret = weston_output_repaint(output);
+	weston_compositor_read_presentation_clock(compositor, now);
 	if (ret != 0)
 		goto err;
 
-	return 0;
+	return;
 
 err:
+	output->next_repaint = 0;
 	weston_output_schedule_repaint_reset(output);
+}
+
+static void
+output_repaint_timer_arm(struct weston_compositor *compositor)
+{
+	struct weston_output *output;
+	uint32_t first_time = 0xffffffff;
+	struct timespec now;
+	uint32_t now_ms;
+
+	wl_list_for_each(output, &compositor->output_list, link) {
+		if (output->next_repaint != 0 &&
+		    output->next_repaint < first_time)
+			first_time = output->next_repaint;
+	}
+	weston_compositor_read_presentation_clock(compositor, &now);
+	now_ms = timespec_to_msec(&now);
+
+	if (first_time == 0xffffffff)
+		return;
+
+	/* Now we switch first_time into relative units for the timer. */
+	if (first_time <= now_ms + 1)
+		first_time = 1;
+	else
+		first_time -= now_ms;
+	wl_event_source_timer_update(compositor->repaint_timer, first_time);
+}
+
+static int
+output_repaint_timer_handler(void *data)
+{
+	struct weston_compositor *compositor = data;
+	struct weston_output *output;
+	struct timespec now;
+
+	weston_compositor_read_presentation_clock(compositor, &now);
+	wl_list_for_each(output, &compositor->output_list, link)
+		weston_output_maybe_repaint(output, &now);
+
+	output_repaint_timer_arm(compositor);
+
 	return 0;
 }
 
@@ -2377,17 +2431,22 @@ weston_output_finish_frame(struct weston_output *output,
 	int32_t refresh_nsec;
 	struct timespec now;
 	struct timespec next;
-	struct timespec remain;
-	int msec_rel = 0;
+	uint32_t now_ms;
+	int msec_rel;
 
 	TL_POINT("core_repaint_finished", TLP_OUTPUT(output),
 		 TLP_VBLANK(stamp), TLP_END);
 
+	weston_compositor_read_presentation_clock(compositor, &now);
+	now_ms = timespec_to_msec(&now);
+
 	/* If we haven't been supplied any timestamp at all, we don't have a
 	 * timebase to work against, so any delay just wastes time. Push a
 	 * repaint as soon as possible so we can get on with it. */
-	if (!stamp)
+	if (!stamp) {
+		output->next_repaint = now_ms;
 		goto out;
+	}
 
 	refresh_nsec = millihz_to_nsec(output->current_mode->refresh);
 	weston_presentation_feedback_present_list(&output->feedback_list,
@@ -2396,12 +2455,11 @@ weston_output_finish_frame(struct weston_output *output,
 						  presented_flags);
 
 	output->frame_time = timespec_to_msec(stamp);
-	weston_compositor_read_presentation_clock(compositor, &now);
 
 	timespec_add_nsec(&next, stamp, refresh_nsec);
 	timespec_add_msec(&next, &next, -compositor->repaint_msec);
-	timespec_sub(&remain, &next, &now);
-	msec_rel = timespec_to_msec(&remain);
+	output->next_repaint = timespec_to_msec(&next);
+	msec_rel = output->next_repaint - now_ms;
 
 	if (msec_rel < -1000 || msec_rel > 1000) {
 		static bool warned;
@@ -2419,13 +2477,10 @@ weston_output_finish_frame(struct weston_output *output,
 	 * the deadline of the next frame, to give clients a more predictable
 	 * timing of the repaint cycle to lock on. */
 	if (presented_flags == WP_PRESENTATION_FEEDBACK_INVALID && msec_rel < 0)
-		msec_rel += refresh_nsec / 1000000;
+		output->next_repaint += refresh_nsec / 1000000;
 
 out:
-	if (msec_rel < 1)
-		output_repaint_timer_handler(output);
-	else
-		wl_event_source_timer_update(output->repaint_timer, msec_rel);
+	output_repaint_timer_arm(compositor);
 }
 
 static void
@@ -2548,8 +2603,10 @@ weston_output_schedule_repaint(struct weston_output *output)
 
 	loop = wl_display_get_event_loop(compositor->wl_display);
 	output->repaint_needed = 1;
-	if (output->repaint_scheduled)
+	if (output->repaint_scheduled) {
+		output_repaint_timer_arm(compositor);
 		return;
+	}
 
 	wl_event_loop_add_idle(loop, idle_repaint, output);
 	output->repaint_scheduled = 1;
@@ -4409,8 +4466,6 @@ weston_output_transform_coordinate(struct weston_output *output,
 static void
 weston_output_enable_undo(struct weston_output *output)
 {
-	wl_event_source_remove(output->repaint_timer);
-
 	wl_global_destroy(output->global);
 
 	pixman_region32_fini(&output->region);
@@ -4592,7 +4647,6 @@ weston_output_enable(struct weston_output *output)
 {
 	struct weston_compositor *c = output->compositor;
 	struct weston_output *iterator;
-	struct wl_event_loop *loop;
 	int x = 0, y = 0;
 
 	assert(output->enable);
@@ -4633,10 +4687,6 @@ weston_output_enable(struct weston_output *output)
 	wl_list_init(&output->feedback_list);
 	wl_list_init(&output->link);
 
-	loop = wl_display_get_event_loop(c->wl_display);
-	output->repaint_timer = wl_event_loop_add_timer(loop,
-					output_repaint_timer_handler, output);
-
 	/* Invert the output id pool and look for the lowest numbered
 	 * switch (the least significant bit).  Take that bit's position
 	 * as our ID, and mark it used in the compositor's output_id_pool.
@@ -5138,6 +5188,9 @@ weston_compositor_create(struct wl_display *display, void *user_data)
 
 	loop = wl_display_get_event_loop(ec->wl_display);
 	ec->idle_source = wl_event_loop_add_timer(loop, idle_handler, ec);
+	ec->repaint_timer =
+		wl_event_loop_add_timer(loop, output_repaint_timer_handler,
+					ec);
 
 	weston_layer_init(&ec->fade_layer, ec);
 	weston_layer_init(&ec->cursor_layer, ec);
diff --git a/libweston/compositor.h b/libweston/compositor.h
index 9cdd682b3..959cd9492 100644
--- a/libweston/compositor.h
+++ b/libweston/compositor.h
@@ -172,7 +172,7 @@ struct weston_output {
 	pixman_region32_t previous_damage;
 	int repaint_needed;
 	int repaint_scheduled;
-	struct wl_event_source *repaint_timer;
+	uint32_t next_repaint;
 	struct weston_output_zoom zoom;
 	int dirty;
 	struct wl_signal frame_signal;
@@ -845,6 +845,7 @@ struct weston_compositor {
 	struct wl_event_source *idle_source;
 	uint32_t idle_inhibit;
 	int idle_time;			/* timeout, s */
+	struct wl_event_source *repaint_timer;
 
 	const struct weston_pointer_grab_interface *default_pointer_grab;
 
-- 
2.11.0



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