Macro BILINEAR_INTERPOLATION_BITS in pixman-private.h selects
the number of fractional bits used for bilinear interpolation.
scaling-test and affine-test have checksums for 4-bit, 7-bit
and 8-bit configurations.
Using _mm_loadl_epi64() to load two pixels at once (pairs of top
and bottom pixels) is faster than loading each pixel separately
and combining them with _mm_set_epi32().
=== cairo-perf-trace ===
before: image firefox-fishtank 66.912 66.931 0.13% 3/3
after: image firefox-fishtank 57.584 58.349 0.74% 3/3
=== lowlevel-blt-bench ===
before: src_8888_8888 = L1: 181.10 L2: 179.14 M:178.08 ( 11.02%) HT:153.22 VT:133.45 R:142.24 RT: 95.32
after: src_8888_8888 = L1: 228.68 L2: 225.75 M:223.98 ( 14.23%) HT:185.32 VT:155.06 R:162.73 RT:102.52
This improvement was suggested by Matt Turner on irc.
When compiling using the win32 build system, config.h is not
available nor needed.
Fixes:
pixman-glyph.c(26) : fatal error C1083: Cannot open include file:
'config.h': No such file or directory
Port of 2ddd1c498b to SSE2.
Uses the pmadd technique described in
http://software.intel.com/sites/landingpage/legacy/mmx/MMX_App_24-16_Bit_Conversion.pdf
Works around lack of packusdw instruction by first sign extending the
values.
fast: src_8888_0565 = L1: 681.40 L2: 689.20 M: 644.76 ( 25.51%) HT:404.42 VT:288.04 R:306.07 RT:150.80 (1619Kops/s)
mmx: src_8888_0565 = L1:2056.03 L2:1985.44 M:1574.91 ( 61.87%) HT:533.10 VT:376.35 R:416.10 RT:178.79 (1833Kops/s)
sse2: src_8888_0565 = L1:3793.42 L2:3653.44 M:1878.83 ( 73.94%) HT:535.03 VT:407.96 R:421.46 RT:163.31 (1727Kops/s)
and for reference, using packusdw
sse4: src_8888_0565 = L1:4396.18 L2:4229.25 M:1904.04 ( 75.18%) HT:559.79 VT:427.96 R:440.06 RT:165.71 (1744Kops/s)
Notice that MMX is faster in the RT case because it can operate on
8-bytes instead of the current 16-bytes for SSE2.
Before bisecting to find the exact test which has failed, we
first need to make sure that the first test is fine (the first
test is "good" and the whole range is "bad"). Otherwise
test 2 gets incorrectly flagged as problematic in the case
if we already got a failure on test 1 right from the start.
Unsigned loop variables are only supported since version 3.0
of OpenMP specification. Changing loop variables to use int32_t
type fixes pixman build problems with path64 compiler.
The destination buffer was initialized with random uint32_t values, so
it started out different on big endian vs. little endian. Fix that by
initializing the buffer with random uint8_t values instead.
Instead of caching these fetchers in the image structure, and then
have the iterator getter call them from there, simply change them to
be iterator getters themselves.
This avoids an extra indirect function call and lets us get rid of the
get_scanline_32/64 fields in pixman_image_t.
Optimizing the unorm_to_unorm functions allows a speedup from:
src_8888_2x10 = L1: 62.08 L2: 60.73 M: 59.61 ( 4.30%) HT: 46.81
VT: 42.17 R: 43.18 RT: 26.01 (325Kops/s)
to:
src_8888_2x10 = L1: 76.94 L2: 78.43 M: 75.87 ( 5.59%) HT: 56.73
VT: 52.39 R: 53.00 RT: 29.29 (363Kops/s)
on a i7 Q720 -based laptop.
The key of the patch is the observation that unorm_to_unorm's work can
more easily be done with a simple multiplication and shift, when the
function is applied repeatedly and the parameters are not compile-time
constants. For instance, converting from 0xfe to 0xfefe (expanding
from 8 bits to 16 bits) can be done by calculating
c = c * 0x101
However, sometimes the result is not a neat replication of all the
bits. For instance, going from 10 bits to 16 bits can be done by
calculating
c = c * 0x401UL >> 4
where the intermediate result is 20 bit wide repetition of the 10-bit
pattern followed by shifting off the unnecessary lowest bits.
The patch has the algorithm to calculate the factor and the shift, and
converts the code to use it.
The flag allows the user to select whether pixman-mmx.c is compiled with
-march=iwmmxt or -march=iwmmxt2.
gcc has scheduling support for the Marvell CPU in the XO 1.75 when
building with -march=iwmmxt2.
gcc has no sane way of enabling iwmmxt code generation, like -msse for
SSE, so you have to use -march=iwmmxt{,2}. User CFLAGS are placed after
-march=iwmmxt and override the march value, so we have to use a custom
build rule to order the CFLAGS such that pixman-mmx.c will be built with
the necessary CFLAGS.
Make _pixman_image_get_solid() faster by special-casing the common
cases where the image is SOLID or a repeating a8r8g8b8 image.
This optimization together with the previous one results in a small
but reproducable performance improvement on the xfce4-terminal-a1
cairo trace:
[ # ] backend test min(s) median(s) stddev. count
Before:
[ 0] image xfce4-terminal-a1 1.221 1.239 1.21% 100/100
After:
[ 0] image xfce4-terminal-a1 1.170 1.199 1.26% 100/100
Either optimization by itself is difficult to separate from noise.
Bypass much of the overhead of pixman_image_composite32() by only
computing the composite region once instead of once per glyph, and by
only looking up the composite function whenever the glyph format or
flags change.
As part of this, the pixman_compute_composite_region32() was renamed
to _pixman_compute_composite_region32() and exported in
pixman-private.h.
I couldn't find a trace that would reliably demonstrate that this is
actually an improvement by itself (since _pixman_composite_glyphs_no_mask()
is called so rarely), but together with the following optimization for
solid sources, there is a small but reliable improvement to the
xfce4-a1-terminal cairo trace.
When adding glyphs to the mask, bypass most of the overhead of
pixman_image_composite32() by:
- Only looking up the composite function when the glyph changes either
format or flags.
- Only using a white source when the glyph format is different from
the mask format.
- Simply intersecting the glyph rectangle with the destination
rectangle instead of doing the full _pixman_composite_region32().
Performance results:
[ # ] backend test min(s) median(s) stddev. count
Before:
[ 0] image firefox-talos-gfx 6.570 6.577 0.13% 8/10
After:
[ 0] image firefox-talos-gfx 4.272 4.289 0.28% 10/10
V2: Changes to deal with white sources
This test tests the new glyph cache and compositing API. Much of this
test is intending to making sure that clipping and alpha map handling
survive any optimizations that may be added to the glyph compositing.
V2: Evaluating lcg_rand_n() multiple times in an argument list lead
to undefined behavior.
When a destination image I has an alpha map A, the following rules apply:
- If I has an alpha channel itself, the content of that channel is
undefined
- If A has RGB channels, the content of those channels is
undefined.
Hence in order to compute the CRC32 for such an image, we have to mask
off the alpha channel of the image, and the RGB channels of the alpha
map.
V2: Shifting by 32 is undefined in C
This new API allows entire glyph strings to be composited in one go
which reduces overhead compared to multiple calls to
pixman_image_composite32().
The pixman_glyph_cache_t is a hash table that maps two keys (a "font"
and a "glyph" key, but they are just keys; there is no distinction
between them as far as pixman is concerned) to a glyph. Glyphs in the
cache can be composited through two new entry points
pixman_glyph_cache_composite_glyphs() and
pixman_glyph_cache_composite_glyphs_no_mask().
A glyph cache may only be inserted into when it is "frozen", which is
achieved by calling pixman_glyph_cache_freeze(). When
pixman_glyph_cache_thaw() is later called, if the cache has become too
crowded, some glyphs (currently the least-recently-used) will
automatically be evicted. This means that a user must ensure that all
the required glyphs are present in the cache before compositing a
string. The intended way to use the cache is like this:
pixman_glyph_t glyphs[MAX_GLYPHS];
pixman_glyph_cache_freeze (cache);
for (i = 0; i < n_glyphs; ++i)
{
const void *g;
if (!(g = pixman_glyph_cache_lookup (cache, font_key, glyph_key)))
{
img = <rasterize glyph as a pixman_image_t>;
g = pixman_glyph_cache_insert (cache, font_key, glyph_key,
glyph_origin_x, glyph_origin_y,
img);
if (!g)
{
/* Clean up out-of-memory condition */
goto oom;
}
glyphs[i].pos_x = glyph_x_pos;
glyphs[i].pos_y = glyph_y_pos;
glyphs[i].glyph = g;
}
}
pixman_composite_glyphs (op, src, dest, ..., cache, n_glyphs, glyphs);
pixman_glyph_cache_thaw (cache);
V2:
- Move glyphs to front of the MRU list when they are used. Pointed
out by Behdad Esfahbod.
- Composite glyphs with (white IN glyph) ADD mask in order to support
mixed a8 and a8r8g8b8 glyphs. Also pointed out by Behdad.
- Add pixman_glyph_get_mask_format
This commit adds some new inline functions to maintain a doubly linked
list.
The way to use them is to embed a pixman_link_t into the structures
that should be linked, and use a pixman_list_t as the head of the
list.
The new functions are
pixman_list_init (pixman_list_t *list);
pixman_list_prepend (pixman_list_t *list, pixman_link_t *link);
pixman_list_move_to_front (pixman_list_t *list, pixman_link_t *link);
There are also a new macro:
CONTAINER_OF(type, member, data);
that can be used to get from a pointer to a member to the containing
structure.
V2: Use the C89 macro offsetof() instead of rolling our own -
suggested by Alan Coopersmith.
Now that we have the full image flags available, the SSE2 and MMX
iterators can simply check against SAMPLES_COVER_CLIP_NEAREST (which
is computed in pixman_image_composite32()) instead of comparing all
the x/y/width/height parameters.
When pixman_image_composite32() is called some flags are computed that
indicate various things about the composite operation that can't be
deduced from the image flags themselves. These additional flags are
not currently available to iterators. All they can do is read the
image flags in image->common.flags.
Fix that by passing the info->{src, mask, dest}_flags on to the
iterator initialization and store the flags in the iter struct as
"image_flags". At the same time rename the *iterator* flags variable
to "iter_flags" to avoid confusion.
There is a couple of places where the test suite uses the
pixman_image_fill_* functions to initialize images. These functions
can fail, and will do so if the "fast" implementation is disabled.
So to make sure the test suite passes even using
PIXMAN_DISABLE="fast", use pixman_image_composite32() with a solid
image instead of pixman_image_fill_*.
In main loop (unrolled by factor 2), instead of negating multiplied
mask values by srca, values of srca was negated, and passed as alpha
argument for
UN8x4_MUL_UN8x4_ADD_UN8x4 macro.
Instead of:
ma = ~ma;
UN8x4_MUL_UN8x4_ADD_UN8x4 (d, ma, s);
Code was doing this:
ma = ~srca;
UN8x4_MUL_UN8x4_ADD_UN8x4 (d, ma, s);
Key is in substituting registers s0/s1 (containing srca value), with
t0/t1 containing mask values multiplied by srca. Register usage is
also improved (less registers are saved on stack, for
over_n_8888_8888_ca routine).
The bug was introduced in commit d2ee5631 and revealed by composite test.
