[PATCH 9/9] presentation-shm: Allow setting of delay before surface.commit

[Mario Kleiner]

A new optional parameter "-d msecs" allows to specify a
delay before the surface attach/damage/commit to shift
the point in time when a surface update is committed.

This allows to test how different client timings interact
with the compositors repaint timing.

Suggested by Pekka Paalanen.

Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
---
 clients/presentation-shm.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/clients/presentation-shm.c b/clients/presentation-shm.c
index e791b2b..e45b623 100644
--- a/clients/presentation-shm.c
+++ b/clients/presentation-shm.c
@@ -101,6 +101,7 @@ struct window {
 	int num_buffers;
 	int next;
 	int refresh_nsec;
+	int commit_delay_msecs;
 
 	struct wl_callback *callback;
 	struct wl_list feedback_list;
@@ -201,19 +202,21 @@ static const struct wl_shell_surface_listener shell_surface_listener = {
 
 static struct window *
 create_window(struct display *display, int width, int height,
-	      enum run_mode mode)
+	      enum run_mode mode, int commit_delay_msecs)
 {
 	struct window *window;
 	char title[128];
 	int ret;
 
 	snprintf(title, sizeof(title),
-		 "presentation-shm: %s", run_mode_name[mode]);
+		 "presentation-shm: %s [Delay %i msecs]", run_mode_name[mode],
+		 commit_delay_msecs);
 
 	window = calloc(1, sizeof *window);
 	if (!window)
 		return NULL;
 
+	window->commit_delay_msecs = commit_delay_msecs;
 	window->mode = mode;
 	window->callback = NULL;
 	wl_list_init(&window->feedback_list);
@@ -490,6 +493,13 @@ window_create_feedback(struct window *window, uint32_t frame_stamp)
 					   &feedback_listener, feedback);
 
 	feedback->frame_no = seq;
+
+	/* Delay by given msecs to test effects of compositor scheduling */
+	if (window->commit_delay_msecs > 0) {
+		struct timespec delay = { 0, window->commit_delay_msecs * 1e6 };
+		clock_nanosleep(window->display->clk_id, 0, &delay, NULL);
+	}
+
 	clock_gettime(window->display->clk_id, &feedback->commit);
 	feedback->frame_stamp = frame_stamp;
 	feedback->target = feedback->commit;
@@ -810,7 +820,8 @@ usage(const char *prog, int exit_code)
 		"  -f\trun in feedback mode (default)\n"
 		"  -i\trun in feedback-idle mode; sleep 1s between frames\n"
 		"  -p\trun in low-latency presentation mode\n"
-		"and 'options' may include\n",
+		"and 'options' may include\n"
+		"  -d msecs\tdelay by given milliseconds before commit\n\n",
 		prog);
 
 	fprintf(stderr, "Printed timing statistics, depending on mode:\n"
@@ -835,6 +846,7 @@ main(int argc, char **argv)
 	int ret = 0;
 	enum run_mode mode = RUN_MODE_FEEDBACK;
 	int i;
+	int commit_delay_msecs = 0;
 
 	for (i = 1; i < argc; i++) {
 		if (strcmp("-f", argv[i]) == 0)
@@ -843,12 +855,16 @@ main(int argc, char **argv)
 			mode = RUN_MODE_FEEDBACK_IDLE;
 		else if (strcmp("-p", argv[i]) == 0)
 			mode = RUN_MODE_PRESENT;
+		else if ((strcmp("-d", argv[i]) == 0) && (i + 1 < argc)) {
+			i++;
+			commit_delay_msecs = atoi(argv[i]);
+		}
 		else
 			usage(argv[0], EXIT_FAILURE);
 	}
 
 	display = create_display();
-	window = create_window(display, 250, 250, mode);
+	window = create_window(display, 250, 250, mode, commit_delay_msecs);
 	if (!window)
 		return 1;
 
-- 
1.9.1