From 413c4914129cd26ca87960852d8c0264c0fb29e7 Mon Sep 17 00:00:00 2001 From: Chad Versace Date: Tue, 4 Sep 2012 12:15:29 -0700 Subject: [PATCH] intel: Improve teximage perf for Google Chrome paint rects (v3) MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This patch reduces the time spent in glTexImage and glTexSubImage by over 5x on Sandybridge for the workload described below. It adds a new fast path for glTexImage2D and glTexSubImage2D, intel_texsubimage_tiled_memcpy, which is optimized for Google Chrome's paint rectangles. The fast path is implemented only for 2D GL_BGRA textures for chipsets with a LLC. === Performance Analysis === Workload description: Personalize your google.com page with a wallpaper. Start chromium with flags "--ignore-gpu-blacklist --enable-accelerated-painting --force-compositing-mode". Start recording with chrome://tracing. Visit google.com and wait for page to finish rendering. Measure the time spent by process CrGpuMain in GLES2DecoderImpl::HandleTexImage2D and HandleTexSubImage2D. System config: cpu: Sandybridge Mobile GT2+ (0x0126) kernel 3.4.9 x86_64 chromium 21.0.1180.89 (154005) Statistics: | N Median Avg Stddev --------------|------------------------- before (msec) | 8 472.5 463.75 72.6 after (msec) | 8 78.0 79.6 5.7 Arithmetic difference at 95.0% confidence: -384.1 +/- 55.2 msec -82.8% +/- 11.9% Ratio at 95.0% confidence: 5.81 +/- 0.119 v2: - Replace check for `intel->gen >= 6` with `intel->has_llc`, per danvet. - Fix typo in comment, s/throuh/through/. - Swap 'before' and 'after' rows in stat table. v3: - If the current batch references the bo, then flush batch before mapping the bo. Found by Chris. - Restrict supported texture images to level 0 of target GL_TEXTURE_2D. This avoids an arithmetic bug in calculating image offsets within the miptree, found by Paul. This restriction does not diminish this patch's benefit to Chrome OS performance. - Use less instructions for bit6 swizzling, suggested by Paul. - Remove erroneous comment about Y-tiling, for Paul. - Print perf_debug messages when flushing and stalling. - Update stats in commit message; run workload under a release build rather than a debug build. Note: This is a candidate for the 9.0 branch. Acked-by: Eric Anholt CC: Stéphane Marchesin Signed-off-by: Chad Versace --- src/mesa/drivers/dri/intel/intel_tex.h | 11 ++ src/mesa/drivers/dri/intel/intel_tex_image.c | 12 ++ .../drivers/dri/intel/intel_tex_subimage.c | 163 ++++++++++++++++++ 3 files changed, 186 insertions(+) diff --git a/src/mesa/drivers/dri/intel/intel_tex.h b/src/mesa/drivers/dri/intel/intel_tex.h index 88a7d55414a..777574ddd9b 100644 --- a/src/mesa/drivers/dri/intel/intel_tex.h +++ b/src/mesa/drivers/dri/intel/intel_tex.h @@ -85,4 +85,15 @@ bool intel_copy_texsubimage(struct intel_context *intel, GLint x, GLint y, GLsizei width, GLsizei height); +bool +intel_texsubimage_tiled_memcpy(struct gl_context *ctx, + GLuint dims, + struct gl_texture_image *texImage, + GLint xoffset, GLint yoffset, GLint zoffset, + GLsizei width, GLsizei height, GLsizei depth, + GLenum format, GLenum type, + const GLvoid *pixels, + const struct gl_pixelstore_attrib *packing, + bool for_glTexImage); + #endif diff --git a/src/mesa/drivers/dri/intel/intel_tex_image.c b/src/mesa/drivers/dri/intel/intel_tex_image.c index a08a5a200b8..7b9638f666a 100644 --- a/src/mesa/drivers/dri/intel/intel_tex_image.c +++ b/src/mesa/drivers/dri/intel/intel_tex_image.c @@ -206,10 +206,22 @@ intelTexImage(struct gl_context * ctx, GLenum format, GLenum type, const void *pixels, const struct gl_pixelstore_attrib *unpack) { + bool ok; + DBG("%s target %s level %d %dx%dx%d\n", __FUNCTION__, _mesa_lookup_enum_by_nr(texImage->TexObject->Target), texImage->Level, texImage->Width, texImage->Height, texImage->Depth); + ok = intel_texsubimage_tiled_memcpy(ctx, dims, texImage, + 0, 0, 0, /*x,y,z offsets*/ + texImage->Width, + texImage->Height, + texImage->Depth, + format, type, pixels, unpack, + true /*for_glTexImage*/); + if (ok) + return; + /* Attempt to use the blitter for PBO image uploads. */ if (dims <= 2 && diff --git a/src/mesa/drivers/dri/intel/intel_tex_subimage.c b/src/mesa/drivers/dri/intel/intel_tex_subimage.c index ae4b3bca305..d3a873655fb 100644 --- a/src/mesa/drivers/dri/intel/intel_tex_subimage.c +++ b/src/mesa/drivers/dri/intel/intel_tex_subimage.c @@ -26,6 +26,7 @@ * **************************************************************************/ +#include "main/macros.h" #include "main/mtypes.h" #include "main/pbo.h" #include "main/texobj.h" @@ -33,6 +34,7 @@ #include "main/texcompress.h" #include "main/enums.h" +#include "intel_batchbuffer.h" #include "intel_context.h" #include "intel_tex.h" #include "intel_mipmap_tree.h" @@ -148,6 +150,157 @@ intel_blit_texsubimage(struct gl_context * ctx, return true; } +/** + * \brief A fast path for glTexImage and glTexSubImage. + * + * \param for_glTexImage Was this called from glTexImage or glTexSubImage? + * + * This fast path is taken when the hardware natively supports the texture + * format (such as GL_BGRA) and when the texture memory is X-tiled. It uploads + * the texture data by mapping the texture memory without a GTT fence, thus + * acquiring a tiled view of the memory, and then memcpy'ing sucessive + * subspans within each tile. + * + * This is a performance win over the conventional texture upload path because + * it avoids the performance penalty of writing through the write-combine + * buffer. In the conventional texture upload path, + * texstore.c:store_texsubimage(), the texture memory is mapped through a GTT + * fence, thus acquiring a linear view of the memory, then each row in the + * image is memcpy'd. In this fast path, we replace each row's memcpy with + * a sequence of memcpy's over each bit6 swizzle span in the row. + * + * This fast path's use case is Google Chrome's paint rectangles. Chrome (as + * of version 21) renders each page as a tiling of 256x256 GL_BGRA textures. + * Each page's content is initially uploaded with glTexImage2D and damaged + * regions are updated with glTexSubImage2D. On some workloads, the + * performance gain of this fastpath on Sandybridge is over 5x. + */ +bool +intel_texsubimage_tiled_memcpy(struct gl_context * ctx, + GLuint dims, + struct gl_texture_image *texImage, + GLint xoffset, GLint yoffset, GLint zoffset, + GLsizei width, GLsizei height, GLsizei depth, + GLenum format, GLenum type, + const GLvoid *pixels, + const struct gl_pixelstore_attrib *packing, + bool for_glTexImage) +{ + struct intel_context *intel = intel_context(ctx); + struct intel_texture_image *image = intel_texture_image(texImage); + + /* The miptree's buffer. */ + drm_intel_bo *bo; + + int error = 0; + + /* This fastpath is restricted to a specific texture type: level 0 of + * a 2D BGRA texture. It could be generalized to support more types by + * varying the arithmetic loop below. + */ + if (!intel->has_llc || + format != GL_BGRA || + type != GL_UNSIGNED_BYTE || + texImage->TexObject->Target != GL_TEXTURE_2D || + texImage->Level != 0 || + pixels == NULL || + packing->Alignment > 4) + return false; + + if (for_glTexImage) + ctx->Driver.AllocTextureImageBuffer(ctx, texImage); + + if (!image->mt || + image->mt->region->tiling != I915_TILING_X) { + /* The algorithm below is written only for X-tiled memory. */ + return false; + } + + bo = image->mt->region->bo; + + if (drm_intel_bo_references(intel->batch.bo, bo)) { + perf_debug("Flushing before mapping a referenced bo.\n"); + intel_batchbuffer_flush(intel); + } + + if (unlikely(INTEL_DEBUG & DEBUG_PERF)) { + if (drm_intel_bo_busy(bo)) { + perf_debug("Mapping a busy BO, causing a stall on the GPU.\n"); + } + } + + error = drm_intel_bo_map(bo, true /*write_enable*/); + if (error || bo->virtual == NULL) { + DBG("%s: failed to map bo\n", __FUNCTION__); + return false; + } + + /* We postponed printing this message until having committed to executing + * the function. + */ + DBG("%s: level=%d offset=(%d,%d) (w,h)=(%d,%d)\n", + __FUNCTION__, texImage->Level, xoffset, yoffset, width, height); + + /* In the tiling algorithm below, some variables are in units of pixels, + * others are in units of bytes, and others (such as height) are unitless. + * Each variable name is suffixed with its units. + */ + + const uint32_t x_max_pixels = xoffset + width; + const uint32_t y_max_pixels = yoffset + height; + + const uint32_t tile_size_bytes = 4096; + + const uint32_t tile_width_bytes = 512; + const uint32_t tile_width_pixels = 128; + + const uint32_t tile_height = 8; + + const uint32_t cpp = 4; /* chars per pixel of GL_BGRA */ + const uint32_t swizzle_width_pixels = 16; + + const uint32_t stride_bytes = image->mt->region->pitch * cpp; + const uint32_t width_tiles = stride_bytes / tile_width_bytes; + + for (uint32_t y_pixels = yoffset; y_pixels < y_max_pixels; ++y_pixels) { + const uint32_t y_offset_bytes = (y_pixels / tile_height) * width_tiles * tile_size_bytes + + (y_pixels % tile_height) * tile_width_bytes; + + for (uint32_t x_pixels = xoffset; x_pixels < x_max_pixels; x_pixels += swizzle_width_pixels) { + const uint32_t x_offset_bytes = (x_pixels / tile_width_pixels) * tile_size_bytes + + (x_pixels % tile_width_pixels) * cpp; + + intptr_t offset_bytes = y_offset_bytes + x_offset_bytes; + if (intel->has_swizzling) { +#if 0 + /* Clear, unoptimized version. */ + bool bit6 = (offset_bytes >> 6) & 1; + bool bit9 = (offset_bytes >> 9) & 1; + bool bit10 = (offset_bytes >> 10) & 1; + + if (bit9 ^ bit10) + offset_bytes ^= (1 << 6); +#else + /* Optimized, obfuscated version. */ + offset_bytes ^= ((offset_bytes >> 3) ^ (offset_bytes >> 4)) + & (1 << 6); +#endif + } + + const uint32_t swizzle_bound_pixels = ALIGN(x_pixels + 1, swizzle_width_pixels); + const uint32_t memcpy_bound_pixels = MIN2(x_max_pixels, swizzle_bound_pixels); + const uint32_t copy_size = cpp * (memcpy_bound_pixels - x_pixels); + + memcpy(bo->virtual + offset_bytes, pixels, copy_size); + pixels += copy_size; + x_pixels -= (x_pixels % swizzle_width_pixels); + } + } + + drm_intel_bo_unmap(bo); + return true; +} + static void intelTexSubImage(struct gl_context * ctx, GLuint dims, @@ -158,6 +311,16 @@ intelTexSubImage(struct gl_context * ctx, const GLvoid * pixels, const struct gl_pixelstore_attrib *packing) { + bool ok; + + ok = intel_texsubimage_tiled_memcpy(ctx, dims, texImage, + xoffset, yoffset, zoffset, + width, height, depth, + format, type, pixels, packing, + false /*for_glTexImage*/); + if (ok) + return; + /* The intel_blit_texsubimage() function only handles 2D images */ if (dims != 2 || !intel_blit_texsubimage(ctx, texImage, xoffset, yoffset, -- 2.30.2