[Pixman] [PATCH 2/2] ssse3: Add iterator for separable bilinear scaling
Søren Sandmann Pedersen
sandmann at cs.au.dk
Thu Aug 29 10:02:53 PDT 2013
This new iterator uses the SSSE3 instructions pmaddubsw and pabsw to
implement a fast iterator for bilinear scaling.
There is a graph here recording the per-pixel time for various
bilinear scaling algorithms as reported by scaling-bench:
http://people.freedesktop.org/~sandmann/ssse3/ssse3.png
As the graph shows, this new iterator is clearly faster than the
existing C iterator, and when used with an SSE2 combiner, it is also
faster than the existing SSE2 fast paths except for the lowest scaling
ratios.
The data was measured on an Ivy Bridge i7-3520M @ 2.0GHz and is
available in this directory:
http://people.freedesktop.org/~sandmann/ssse3/
where there is also a Gnumeric spreadsheet ssse3.gnumeric containing
the per-pixel values and the graph.
---
pixman/pixman-ssse3.c | 312 +++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 312 insertions(+), 0 deletions(-)
diff --git a/pixman/pixman-ssse3.c b/pixman/pixman-ssse3.c
index 19d71e7..98d929b 100644
--- a/pixman/pixman-ssse3.c
+++ b/pixman/pixman-ssse3.c
@@ -35,6 +35,316 @@
#include "pixman-private.h"
#include "pixman-inlines.h"
+typedef struct
+{
+ int y;
+ uint64_t * buffer;
+} line_t;
+
+typedef struct
+{
+ line_t line0;
+ line_t line1;
+ pixman_fixed_t y;
+ pixman_fixed_t x;
+ uint64_t data[1];
+} bilinear_info_t;
+
+static void
+ssse3_fetch_horizontal (bits_image_t *image, line_t *line,
+ int y, pixman_fixed_t x, pixman_fixed_t ux, int n)
+{
+ uint32_t *bits = image->bits + y * image->rowstride;
+ __m128i vx = _mm_set_epi16 (
+ - (x + 1), x, - (x + 1), x,
+ - (x + ux + 1), x + ux, - (x + ux + 1), x + ux);
+ __m128i vux = _mm_set_epi16 (
+ - 2 * ux, 2 * ux, - 2 * ux, 2 * ux,
+ - 2 * ux, 2 * ux, - 2 * ux, 2 * ux);
+ __m128i vaddc = _mm_set_epi16 (1, 0, 1, 0, 1, 0, 1, 0);
+ __m128i *b = (__m128i *)line->buffer;
+ __m128i vrl0, vrl1;
+
+ while ((n -= 2) >= 0)
+ {
+ __m128i vw, vr, s;
+
+ vrl1 = _mm_loadl_epi64 (
+ (__m128i *)(bits + pixman_fixed_to_int (x + ux)));
+ /* vrl1: R1, L1 */
+
+ final_pixel:
+ vrl0 = _mm_loadl_epi64 (
+ (__m128i *)(bits + pixman_fixed_to_int (x)));
+ /* vrl0: R0, L0 */
+
+ /* The weights are based on vx which is a vector of
+ *
+ * - (x + 1), x, - (x + 1), x,
+ * - (x + ux + 1), x + ux, - (x + ux + 1), x + ux
+ *
+ * so the 16 bit weights end up like this:
+ *
+ * iw0, w0, iw0, w0, iw1, w1, iw1, w1
+ *
+ * and after shifting and packing, we get these bytes:
+ *
+ * iw0, w0, iw0, w0, iw1, w1, iw1, w1,
+ * iw0, w0, iw0, w0, iw1, w1, iw1, w1,
+ *
+ * which means the first and the second input pixel
+ * have to be interleaved like this:
+ *
+ * la0, ra0, lr0, rr0, la1, ra1, lr1, rr1,
+ * lg0, rg0, lb0, rb0, lg1, rg1, lb1, rb1
+ *
+ * before maddubsw can be used.
+ */
+
+ vw = _mm_add_epi16 (
+ vaddc, _mm_srli_epi16 (vx, 16 - BILINEAR_INTERPOLATION_BITS));
+ /* vw: iw0, w0, iw0, w0, iw1, w1, iw1, w1
+ */
+
+ vw = _mm_packus_epi16 (vw, vw);
+ /* vw: iw0, w0, iw0, w0, iw1, w1, iw1, w1,
+ * iw0, w0, iw0, w0, iw1, w1, iw1, w1
+ */
+ vx = _mm_add_epi16 (vx, vux);
+
+ x += 2 * ux;
+
+ vr = _mm_unpacklo_epi16 (vrl1, vrl0);
+ /* vr: rar0, rar1, rgb0, rgb1, lar0, lar1, lgb0, lgb1 */
+
+ s = _mm_shuffle_epi32 (vr, _MM_SHUFFLE (1, 0, 3, 2));
+ /* s: lar0, lar1, lgb0, lgb1, rar0, rar1, rgb0, rgb1 */
+
+ vr = _mm_unpackhi_epi8 (vr, s);
+ /* vr: la0, ra0, lr0, rr0, la1, ra1, lr1, rr1,
+ * lg0, rg0, lb0, rb0, lg1, rg1, lb1, rb1
+ */
+
+ vr = _mm_maddubs_epi16 (vr, vw);
+
+ /* When the weight is 0, the inverse weight is
+ * 128 which can't be represented in a signed byte.
+ * As a result maddubsw computes the following:
+ *
+ * r = l * -128 + r * 0
+ *
+ * rather than the desired
+ *
+ * r = l * 128 + r * 0
+ *
+ * We fix this by taking the absolute value of the
+ * result.
+ */
+ vr = _mm_abs_epi16 (vr);
+
+ /* vr: A0, R0, A1, R1, G0, B0, G1, B1 */
+ _mm_store_si128 (b++, vr);
+ }
+
+ if (n == -1)
+ {
+ vrl1 = _mm_setzero_si128();
+ goto final_pixel;
+ }
+
+ line->y = y;
+}
+
+static uint32_t *
+ssse3_fetch_bilinear_cover (pixman_iter_t *iter, const uint32_t *mask)
+{
+ pixman_fixed_t fx, ux;
+ bilinear_info_t *info = iter->data;
+ line_t *line0, *line1;
+ int y0, y1;
+ int32_t dist_y;
+ __m128i vw;
+ int i;
+
+ fx = info->x;
+ ux = iter->image->common.transform->matrix[0][0];
+
+ y0 = pixman_fixed_to_int (info->y);
+ y1 = y0 + 1;
+
+ line0 = &info->line0;
+ line1 = &info->line1;
+
+ if (line0->y != y0 || line1->y != y1)
+ {
+ if (line0->y == y1 || line1->y == y0)
+ {
+ line_t tmp = *line0;
+ *line0 = *line1;
+ *line1 = tmp;
+ }
+
+ if (line0->y != y0)
+ {
+ ssse3_fetch_horizontal (
+ &iter->image->bits, line0, y0, fx, ux, iter->width);
+ }
+
+ if (line1->y != y1)
+ {
+ ssse3_fetch_horizontal (
+ &iter->image->bits, line1, y1, fx, ux, iter->width);
+ }
+ }
+
+ dist_y = pixman_fixed_to_bilinear_weight (info->y);
+ dist_y <<= (16 - BILINEAR_INTERPOLATION_BITS);
+
+ vw = _mm_set_epi16 (
+ dist_y, dist_y, dist_y, dist_y, dist_y, dist_y, dist_y, dist_y);
+
+ for (i = 0; i + 3 < iter->width; i += 4)
+ {
+ __m128i top0 = _mm_load_si128 ((__m128i *)(line0->buffer + i));
+ __m128i bot0 = _mm_load_si128 ((__m128i *)(line1->buffer + i));
+ __m128i top1 = _mm_load_si128 ((__m128i *)(line0->buffer + i + 2));
+ __m128i bot1 = _mm_load_si128 ((__m128i *)(line1->buffer + i + 2));
+ __m128i r0, r1, tmp, p;
+
+ r0 = _mm_mulhi_epu16 (
+ _mm_sub_epi16 (bot0, top0), vw);
+ tmp = _mm_cmplt_epi16 (bot0, top0);
+ tmp = _mm_and_si128 (tmp, vw);
+ r0 = _mm_sub_epi16 (r0, tmp);
+ r0 = _mm_add_epi16 (r0, top0);
+ r0 = _mm_srli_epi16 (r0, BILINEAR_INTERPOLATION_BITS);
+ /* r0: A0 R0 A1 R1 G0 B0 G1 B1 */
+ r0 = _mm_shuffle_epi32 (r0, _MM_SHUFFLE (2, 0, 3, 1));
+ /* r0: A1 R1 G1 B1 A0 R0 G0 B0 */
+
+ r1 = _mm_mulhi_epu16 (
+ _mm_sub_epi16 (bot1, top1), vw);
+ tmp = _mm_cmplt_epi16 (bot1, top1);
+ tmp = _mm_and_si128 (tmp, vw);
+ r1 = _mm_sub_epi16 (r1, tmp);
+ r1 = _mm_add_epi16 (r1, top1);
+ r1 = _mm_srli_epi16 (r1, BILINEAR_INTERPOLATION_BITS);
+ r1 = _mm_shuffle_epi32 (r1, _MM_SHUFFLE (2, 0, 3, 1));
+ /* r1: A3 R3 G3 B3 A2 R2 G2 B2 */
+
+ p = _mm_packus_epi16 (r0, r1);
+
+ _mm_store_si128 ((__m128i *)(iter->buffer + i), p);
+ }
+
+ while (i < iter->width)
+ {
+ __m128i top0 = _mm_load_si128 ((__m128i *)(line0->buffer + i));
+ __m128i bot0 = _mm_load_si128 ((__m128i *)(line1->buffer + i));
+ __m128i r0, tmp, p;
+
+ r0 = _mm_mulhi_epu16 (
+ _mm_sub_epi16 (bot0, top0), vw);
+ tmp = _mm_cmplt_epi16 (bot0, top0);
+ tmp = _mm_and_si128 (tmp, vw);
+ r0 = _mm_sub_epi16 (r0, tmp);
+ r0 = _mm_add_epi16 (r0, top0);
+ r0 = _mm_srli_epi16 (r0, BILINEAR_INTERPOLATION_BITS);
+ /* r0: A0 R0 A1 R1 G0 B0 G1 B1 */
+ r0 = _mm_shuffle_epi32 (r0, _MM_SHUFFLE (2, 0, 3, 1));
+ /* r0: A1 R1 G1 B1 A0 R0 G0 B0 */
+
+ p = _mm_packus_epi16 (r0, r0);
+
+ if (iter->width - i == 1)
+ {
+ *(uint32_t *)(iter->buffer + i) = _mm_cvtsi128_si32 (p);
+ i++;
+ }
+ else
+ {
+ *(uint64_t *)(iter->buffer + i) = _mm_cvtsi128_si64 (p);
+ i += 2;
+ }
+ }
+
+ info->y += iter->image->common.transform->matrix[1][1];
+
+ return iter->buffer;
+}
+
+static void
+ssse3_bilinear_cover_iter_fini (pixman_iter_t *iter)
+{
+ free (iter->data);
+}
+
+static void
+ssse3_bilinear_cover_iter_init (pixman_iter_t *iter, const pixman_iter_info_t *iter_info)
+{
+ int width = iter->width;
+ bilinear_info_t *info;
+ pixman_vector_t v;
+
+ /* Reference point is the center of the pixel */
+ v.vector[0] = pixman_int_to_fixed (iter->x) + pixman_fixed_1 / 2;
+ v.vector[1] = pixman_int_to_fixed (iter->y) + pixman_fixed_1 / 2;
+ v.vector[2] = pixman_fixed_1;
+
+ if (!pixman_transform_point_3d (iter->image->common.transform, &v))
+ goto fail;
+
+ info = malloc (sizeof (*info) + (2 * width - 1) * sizeof (uint64_t) + 64);
+ if (!info)
+ goto fail;
+
+ info->x = v.vector[0] - pixman_fixed_1 / 2;
+ info->y = v.vector[1] - pixman_fixed_1 / 2;
+
+#define ALIGN(addr) \
+ ((void *)((((unsigned long)(addr)) + 15) & (~15)))
+
+ /* It is safe to set the y coordinates to -1 initially
+ * because COVER_CLIP_BILINEAR ensures that we will only
+ * be asked to fetch lines in the [0, height) interval
+ */
+ info->line0.y = -1;
+ info->line0.buffer = ALIGN (&(info->data[0]));
+ info->line1.y = -1;
+ info->line1.buffer = ALIGN (info->line0.buffer + width);
+
+ iter->get_scanline = ssse3_fetch_bilinear_cover;
+ iter->fini = ssse3_bilinear_cover_iter_fini;
+
+ iter->data = info;
+ return;
+
+fail:
+ /* Something went wrong, either a bad matrix or OOM; in such cases,
+ * we don't guarantee any particular rendering.
+ */
+ _pixman_log_error (
+ FUNC, "Allocation failure or bad matrix, skipping rendering\n");
+
+ iter->get_scanline = _pixman_iter_get_scanline_noop;
+ iter->fini = NULL;
+}
+
+static const pixman_iter_info_t ssse3_iters[] =
+{
+ { PIXMAN_a8r8g8b8,
+ (FAST_PATH_STANDARD_FLAGS |
+ FAST_PATH_SCALE_TRANSFORM |
+ FAST_PATH_BILINEAR_FILTER |
+ FAST_PATH_SAMPLES_COVER_CLIP_BILINEAR),
+ ITER_NARROW | ITER_SRC,
+ ssse3_bilinear_cover_iter_init,
+ NULL, NULL
+ },
+
+ { PIXMAN_null },
+};
+
static const pixman_fast_path_t ssse3_fast_paths[] =
{
{ PIXMAN_OP_NONE },
@@ -46,5 +356,7 @@ _pixman_implementation_create_ssse3 (pixman_implementation_t *fallback)
pixman_implementation_t *imp =
_pixman_implementation_create (fallback, ssse3_fast_paths);
+ imp->iter_info = ssse3_iters;
+
return imp;
}
--
1.7.1
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