[igt-dev] [PATCH i-g-t 2/2] tests/kms_plane: Pipeline crc capture and flips

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Eliminate some dead time used to wait for crcs by pipelining
the flips and crc capture.

On KBL:
time kms_plane --r pixel-format-pipe-A-planes
- real	0m22,592s
+ real	0m14,527s

time kms_plane --r pixel-format-pipe-A-planes --extended
- real	1m8,090s
+ real	0m38,738s

To keep the code somewhat sane we only pipeline while
capturing the colors for a single pixel format. That does
still leave a few non-pipelined frames when switching from
one pixel format to another. Which explains why the extended
test gets closer to the -50% mark as it tests more colors and
thus has a larger proportion of optimally pipelined flips.

Not sure how horrible the code would become if we tried to
maintain the pipelining throughout the test. For now let's
just accept the small victory and move on.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 tests/kms_plane.c | 70 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 48 insertions(+), 22 deletions(-)

diff --git a/tests/kms_plane.c b/tests/kms_plane.c
index 9ef3a7f3c1b0..9ad366824c0d 100644
--- a/tests/kms_plane.c
+++ b/tests/kms_plane.c
@@ -500,8 +500,9 @@ static void test_format_plane_color(data_t *data, enum pipe pipe,
 		igt_plane_set_size(plane, width, height);
 	}
 
+	if (crc)
+		igt_pipe_crc_get_previous(data->drm_fd, data->pipe_crc, crc);
 	igt_display_commit2(&data->display, data->display.is_atomic ? COMMIT_ATOMIC : COMMIT_UNIVERSAL);
-	igt_pipe_crc_get_current(data->display.drm_fd, data->pipe_crc, crc);
 
 	igt_remove_fb(data->drm_fd, &old_fb);
 }
@@ -525,6 +526,42 @@ static int num_unique_crcs(const igt_crc_t crc[], int num_crc)
 	return num_unique_crc;
 }
 
+static void capture_format_crcs(data_t *data, enum pipe pipe,
+				igt_plane_t *plane,
+				uint32_t format, uint64_t modifier,
+				int width, int height,
+				enum igt_color_encoding encoding,
+				enum igt_color_range range,
+				igt_crc_t crc[], struct igt_fb *fb)
+{
+	int i;
+
+	for (i = 0; i < data->num_colors; i++) {
+		const color_t *c = &data->colors[i];
+
+		/*
+		 * The flip issued during frame N will latch
+		 * at the start of frame N+1, and its CRC will
+		 * be ready at the start of frame N+2. So the
+		 * CRC captured here before the flip is issued
+		 * is for frame N-2.
+		 */
+		test_format_plane_color(data, pipe, plane, format, modifier,
+					width, height, encoding, range, c,
+					i >= 2 ? &crc[i - 2] : NULL, fb);
+	}
+
+	/*
+	 * Get the remaining two crcs
+	 *
+	 * TODO: avoid the extra wait by maintaining the pipeline
+	 * between different pixel formats as well? Could get messy.
+	 */
+	igt_pipe_crc_get_previous(data->drm_fd, data->pipe_crc, &crc[i - 2]);
+	i++;
+	igt_pipe_crc_get_current(data->drm_fd, data->pipe_crc, &crc[i - 2]);
+}
+
 static bool test_format_plane_colors(data_t *data, enum pipe pipe,
 				     igt_plane_t *plane,
 				     uint32_t format, uint64_t modifier,
@@ -534,21 +571,17 @@ static bool test_format_plane_colors(data_t *data, enum pipe pipe,
 				     igt_crc_t ref_crc[],
 				     struct igt_fb *fb)
 {
-	int crc_mismatch_count = 0;
+	igt_crc_t crc[ARRAY_SIZE(colors_extended)];
 	unsigned int crc_mismatch_mask = 0;
+	int crc_mismatch_count = 0;
 	bool result = true;
+	int i;
 
-	for (int i = 0; i < data->num_colors; i++) {
-		const color_t *c = &data->colors[i];
-		igt_crc_t crc;
-
-		test_format_plane_color(data, pipe, plane,
-					format, modifier,
-					width, height,
-					encoding, range,
-					c, &crc, fb);
+	capture_format_crcs(data, pipe, plane, format, modifier,
+			    width, height, encoding, range, crc, fb);
 
-		if (!igt_check_crc_equal(&crc, &ref_crc[i])) {
+	for (i = 0; i < data->num_colors; i++) {
+		if (!igt_check_crc_equal(&crc[i], &ref_crc[i])) {
 			crc_mismatch_count++;
 			crc_mismatch_mask |= (1 << i);
 			result = false;
@@ -700,16 +733,9 @@ static bool test_format_plane(data_t *data, enum pipe pipe,
 		igt_remove_fb(data->drm_fd, &test_fb);
 	}
 
-	for (int i = 0; i < data->num_colors; i++) {
-		const color_t *c = &data->colors[i];
-
-		test_format_plane_color(data, pipe, plane,
-					format, modifier,
-					width, height,
-					IGT_COLOR_YCBCR_BT709,
-					IGT_COLOR_YCBCR_LIMITED_RANGE,
-					c, &ref_crc[i], &fb);
-	}
+	capture_format_crcs(data, pipe, plane, format, modifier,
+			    width, height, IGT_COLOR_YCBCR_BT709,
+			    IGT_COLOR_YCBCR_LIMITED_RANGE, ref_crc, &fb);
 
 	/*
 	 * Make sure we have some difference between the colors. This
-- 
2.24.1