Mesa (lp-binning): llvmpipe: optimize tile writing code
Brian Paul
brianp at kemper.freedesktop.org
Thu Jan 21 16:08:21 UTC 2010
Module: Mesa
Branch: lp-binning
Commit: 63f249bf909cab60635c2df9122db86eaab6c421
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=63f249bf909cab60635c2df9122db86eaab6c421
Author: Brian Paul <brianp at vmware.com>
Date: Wed Jan 20 17:48:09 2010 -0700
llvmpipe: optimize tile writing code
The code which converts/copies color tiles to the linear layout has
been rewritten. There's less arithmetic and better loop unrolling,
and possibly a better memory access pattern.
Some demos, like gears, are about 20% faster now.
---
src/gallium/drivers/llvmpipe/lp_tile_soa.py | 127 +++++++++++++++++++++++----
1 files changed, 109 insertions(+), 18 deletions(-)
diff --git a/src/gallium/drivers/llvmpipe/lp_tile_soa.py b/src/gallium/drivers/llvmpipe/lp_tile_soa.py
index a603b7f..5d53689 100644
--- a/src/gallium/drivers/llvmpipe/lp_tile_soa.py
+++ b/src/gallium/drivers/llvmpipe/lp_tile_soa.py
@@ -129,22 +129,8 @@ def generate_format_read(format, dst_type, dst_native_type, dst_suffix):
print
-def generate_format_write(format, src_type, src_native_type, src_suffix):
- '''Generate the function to write pixels to a particular format'''
-
- name = short_name(format)
-
- dst_native_type = native_type(format)
-
- print 'static void'
- print 'lp_tile_%s_write_%s(const %s *src, uint8_t *dst, unsigned dst_stride, unsigned x0, unsigned y0, unsigned w, unsigned h)' % (name, src_suffix, src_native_type)
- print '{'
- print ' unsigned x, y;'
- print ' uint8_t *dst_row = dst + y0*dst_stride;'
- print ' for (y = 0; y < h; ++y) {'
- print ' %s *dst_pixel = (%s *)(dst_row + x0*%u);' % (dst_native_type, dst_native_type, format.stride())
- print ' for (x = 0; x < w; ++x) {'
-
+def compute_inverse_swizzle(format):
+ '''Return an array[4] of inverse swizzle terms'''
inv_swizzle = [None]*4
if format.colorspace == 'rgb':
for i in range(4):
@@ -155,8 +141,86 @@ def generate_format_write(format, src_type, src_native_type, src_suffix):
swizzle = format.out_swizzle[0]
if swizzle < 4:
inv_swizzle[swizzle] = 0
- else:
- assert False
+ return inv_swizzle
+
+
+def pack_rgba(format, src_type, r, g, b, a):
+ """Return an expression for packing r, g, b, a into a pixel of the
+ given format. Ex: '(b << 24) | (g << 16) | (r << 8) | (a << 0)'
+ """
+ assert format.colorspace == 'rgb'
+ inv_swizzle = compute_inverse_swizzle(format)
+ shift = 0
+ expr = None
+ for i in range(4):
+ # choose r, g, b, or a depending on the inverse swizzle term
+ if inv_swizzle[i] == 0:
+ value = r
+ elif inv_swizzle[i] == 1:
+ value = g
+ elif inv_swizzle[i] == 2:
+ value = b
+ elif inv_swizzle[i] == 3:
+ value = a
+ else:
+ value = None
+
+ if value:
+ dst_type = format.in_types[i]
+ dst_native_type = native_type(format)
+ value = conversion_expr(src_type, dst_type, dst_native_type, value)
+ term = "((%s) << %d)" % (value, shift)
+ if expr:
+ expr = expr + " | " + term
+ else:
+ expr = term
+
+ width = format.in_types[i].size
+ shift = shift + width
+ return expr
+
+
+def emit_unrolled_write_code(format, src_type):
+ '''Emit code for writing a block based on unrolled loops.
+ This is considerably faster than the TILE_PIXEL-based code below.
+ '''
+ dst_native_type = native_type(format)
+ print ' const unsigned dstpix_stride = dst_stride / %d;' % format.stride()
+ print ' %s *dstpix = (%s *) dst;' % (dst_native_type, dst_native_type)
+ print ' unsigned int qx, qy, i;'
+ print
+ print ' for (qy = 0; qy < h; qy += TILE_VECTOR_HEIGHT) {'
+ print ' const unsigned py = y0 + qy;'
+ print ' for (qx = 0; qx < w; qx += TILE_VECTOR_WIDTH) {'
+ print ' const unsigned px = x0 + qx;'
+ print ' const uint8_t *r = src + 0 * TILE_C_STRIDE;'
+ print ' const uint8_t *g = src + 1 * TILE_C_STRIDE;'
+ print ' const uint8_t *b = src + 2 * TILE_C_STRIDE;'
+ print ' const uint8_t *a = src + 3 * TILE_C_STRIDE;'
+ print ' (void) r; (void) g; (void) b; (void) a; /* silence warnings */'
+ print ' for (i = 0; i < TILE_C_STRIDE; i += 2) {'
+ print ' const uint32_t pixel0 = %s;' % pack_rgba(format, src_type, "r[i+0]", "g[i+0]", "b[i+0]", "a[i+0]")
+ print ' const uint32_t pixel1 = %s;' % pack_rgba(format, src_type, "r[i+1]", "g[i+1]", "b[i+1]", "a[i+1]")
+ print ' const unsigned offset = (py + tile_y_offset[i]) * dstpix_stride + (px + tile_x_offset[i]);'
+ print ' dstpix[offset + 0] = pixel0;'
+ print ' dstpix[offset + 1] = pixel1;'
+ print ' }'
+ print ' src += TILE_X_STRIDE;'
+ print ' }'
+ print ' }'
+
+
+def emit_tile_pixel_write_code(format, src_type):
+ '''Emit code for writing a block based on the TILE_PIXEL macro.'''
+ dst_native_type = native_type(format)
+
+ inv_swizzle = compute_inverse_swizzle(format)
+
+ print ' unsigned x, y;'
+ print ' uint8_t *dst_row = dst + y0*dst_stride;'
+ print ' for (y = 0; y < h; ++y) {'
+ print ' %s *dst_pixel = (%s *)(dst_row + x0*%u);' % (dst_native_type, dst_native_type, format.stride())
+ print ' for (x = 0; x < w; ++x) {'
if format.layout == ARITH:
print ' %s pixel = 0;' % dst_native_type
@@ -185,6 +249,20 @@ def generate_format_write(format, src_type, src_native_type, src_suffix):
print ' }'
print ' dst_row += dst_stride;'
print ' }'
+
+
+def generate_format_write(format, src_type, src_native_type, src_suffix):
+ '''Generate the function to write pixels to a particular format'''
+
+ name = short_name(format)
+
+ print 'static void'
+ print 'lp_tile_%s_write_%s(const %s *src, uint8_t *dst, unsigned dst_stride, unsigned x0, unsigned y0, unsigned w, unsigned h)' % (name, src_suffix, src_native_type)
+ print '{'
+ if format.layout == ARITH and format.colorspace == 'rgb':
+ emit_unrolled_write_code(format, src_type)
+ else:
+ emit_tile_pixel_write_code(format, src_type)
print '}'
print
@@ -265,6 +343,19 @@ def main():
print ' { 10, 11, 14, 15}'
print '};'
print
+ print '/* Note: these lookup tables could be replaced with some'
+ print ' * bit-twiddling code, but this is a little faster.'
+ print ' */'
+ print 'static unsigned tile_x_offset[TILE_VECTOR_WIDTH * TILE_VECTOR_HEIGHT] = {'
+ print ' 0, 1, 0, 1, 2, 3, 2, 3,'
+ print ' 0, 1, 0, 1, 2, 3, 2, 3'
+ print '};'
+ print
+ print 'static unsigned tile_y_offset[TILE_VECTOR_WIDTH * TILE_VECTOR_HEIGHT] = {'
+ print ' 0, 0, 1, 1, 0, 0, 1, 1,'
+ print ' 2, 2, 3, 3, 2, 2, 3, 3'
+ print '};'
+ print
generate_clamp()
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