[Pixman] [PATCH] bits: Special case src_iter for 1x1R images

[Chris Wilson]

These are often used inplace of a solid-fill gradient, with the
expectation that have similar performance and hit the same fast paths.
One exception is the identification of the 1x1R <-> solid-fill
equivalence in general_composite_rect(). By adding the special case to
_pixman_bits_image_src_iter_init, we can recover the lost performance:

./tests/lowlevel-blt-bench -n src_n_8888 on a core2 @ 2.66Ghz:

before: add_n_8888 =  L1:   4.52  L2:   4.42  M:  1.63 (  0.13%)  HT:  1.67  VT:  1.65  R:  1.64  RT:  1.59 (  21Kops/s)

after:  add_n_8888 =  L1:1160.10  L2:1296.63  M:581.81 ( 47.46%)  HT:379.06  VT:307.07  R:239.88  RT: 79.37 ( 466Kops/s)

For reference, ./tests/lowlevel-blt-bench src_n_8888:
        add_n_8888 =  L1:1116.99  L2:1254.43  M:578.46 ( 47.50%)  HT:369.20  VT:302.21  R:236.18  RT: 76.64 ( 750Kops/s)

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 pixman/pixman-bits-image.c |   11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/pixman/pixman-bits-image.c b/pixman/pixman-bits-image.c
index 75a39a1..b15305c 100644
--- a/pixman/pixman-bits-image.c
+++ b/pixman/pixman-bits-image.c
@@ -1496,6 +1496,17 @@ _pixman_bits_image_src_iter_init (pixman_image_t *image, pixman_iter_t *iter)
     pixman_format_code_t format = image->common.extended_format_code;
     uint32_t flags = image->common.flags;
     const fetcher_info_t *info;
+    bits_image_t *bits  = &image->bits;
+
+    if ((bits->width | bits->height) == 1 && image->common.repeat)
+    {
+	if (iter->iter_flags & ITER_NARROW)
+	    replicate_pixel_32 (bits, 0, 0, iter->width, iter->buffer);
+	else
+	    replicate_pixel_float (bits, 0, 0, iter->width, iter->buffer);
+	iter->get_scanline = _pixman_iter_get_scanline_noop;
+	return;
+    }
 
     for (info = fetcher_info; info->format != PIXMAN_null; ++info)
     {
-- 
1.7.10.4