Cache the results of get_pixel_formats_to_try
Choosing pixel formats is quite slow (depending on driver?). We were
doing this once per context, and it added up. On my desktop windows
machine, this saves another 7 seconds in `dm --config gl --src gm`.
Actual times:
37s -> 30s (not writing PNGs)
47s -> 39.5s (writing PNGs)
We always called this with MSAA sample count set to zero, so I cleaned
up the code to make that clearer. Also included a comment about the
theoretical risk, although I think that outside of a multi-GPU system,
we're fine.
Bug: skia:
Change-Id: I50927ebfaf6fe8d88a63674427fbf9e06e4ab059
Reviewed-on: https://skia-review.googlesource.com/35763
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/src/utils/win/SkWGL.h b/src/utils/win/SkWGL.h
index 315be24..c6c9479 100644
--- a/src/utils/win/SkWGL.h
+++ b/src/utils/win/SkWGL.h
@@ -143,8 +143,8 @@
*/
class SkWGLPbufferContext : public SkRefCnt {
public:
- static SkWGLPbufferContext* Create(HDC parentDC, int msaaSampleCount,
- SkWGLContextRequest contextType, HGLRC shareContext);
+ static SkWGLPbufferContext* Create(HDC parentDC, SkWGLContextRequest contextType,
+ HGLRC shareContext);
virtual ~SkWGLPbufferContext();
diff --git a/src/utils/win/SkWGL_win.cpp b/src/utils/win/SkWGL_win.cpp
index cc95f49..016b61b 100644
--- a/src/utils/win/SkWGL_win.cpp
+++ b/src/utils/win/SkWGL_win.cpp
@@ -438,8 +438,7 @@
return create_gl_context(dc, extensions, contextType, shareContext);
}
-SkWGLPbufferContext* SkWGLPbufferContext::Create(HDC parentDC, int msaaSampleCount,
- SkWGLContextRequest contextType,
+SkWGLPbufferContext* SkWGLPbufferContext::Create(HDC parentDC, SkWGLContextRequest contextType,
HGLRC shareContext) {
SkWGLExtensions extensions;
if (!extensions.hasExtension(parentDC, "WGL_ARB_pixel_format") ||
@@ -447,24 +446,45 @@
return nullptr;
}
+ // We cache the pixel formats once, and then reuse them. That's possibly incorrect if
+ // there are multiple GPUs, but this function is always called with a freshly made,
+ // identically constructed HDC (see WinGLTestContext).
+ //
+ // We only store two potential pixel formats, one for single buffer, one for double buffer.
+ // We never ask for MSAA, so we don't need the second pixel format for each buffering state.
+ static int gPixelFormats[2] = { -1, -1 };
+ static SkOnce once;
+ once([=] {
+ {
+ // Single buffer
+ int pixelFormatsToTry[2] = { -1, -1 };
+ get_pixel_formats_to_try(parentDC, extensions, false, 0, false, pixelFormatsToTry);
+ gPixelFormats[0] = pixelFormatsToTry[0];
+ }
+ {
+ // Double buffer
+ int pixelFormatsToTry[2] = { -1, -1 };
+ get_pixel_formats_to_try(parentDC, extensions, true, 0, false, pixelFormatsToTry);
+ gPixelFormats[1] = pixelFormatsToTry[0];
+ }
+ });
+
// try for single buffer first
- for (int dblBuffer = 0; dblBuffer < 2; ++dblBuffer) {
- int pixelFormatsToTry[] = { -1, -1 };
- get_pixel_formats_to_try(parentDC, extensions, (0 != dblBuffer), msaaSampleCount,
- false, pixelFormatsToTry);
- for (int f = 0; -1 != pixelFormatsToTry[f] && f < SK_ARRAY_COUNT(pixelFormatsToTry); ++f) {
- HPBUFFER pbuf = extensions.createPbuffer(parentDC, pixelFormatsToTry[f], 1, 1, nullptr);
- if (0 != pbuf) {
- HDC dc = extensions.getPbufferDC(pbuf);
- if (dc) {
- HGLRC glrc = create_gl_context(dc, extensions, contextType, shareContext);
- if (glrc) {
- return new SkWGLPbufferContext(pbuf, dc, glrc);
- }
- extensions.releasePbufferDC(pbuf, dc);
+ for (int pixelFormat : gPixelFormats) {
+ if (-1 == pixelFormat) {
+ continue;
+ }
+ HPBUFFER pbuf = extensions.createPbuffer(parentDC, pixelFormat, 1, 1, nullptr);
+ if (0 != pbuf) {
+ HDC dc = extensions.getPbufferDC(pbuf);
+ if (dc) {
+ HGLRC glrc = create_gl_context(dc, extensions, contextType, shareContext);
+ if (glrc) {
+ return new SkWGLPbufferContext(pbuf, dc, glrc);
}
- extensions.destroyPbuffer(pbuf);
+ extensions.releasePbufferDC(pbuf, dc);
}
+ extensions.destroyPbuffer(pbuf);
}
}
return nullptr;
diff --git a/tools/gpu/gl/win/CreatePlatformGLTestContext_win.cpp b/tools/gpu/gl/win/CreatePlatformGLTestContext_win.cpp
index 49d7743..0e97153 100644
--- a/tools/gpu/gl/win/CreatePlatformGLTestContext_win.cpp
+++ b/tools/gpu/gl/win/CreatePlatformGLTestContext_win.cpp
@@ -90,7 +90,7 @@
winShareContext = shareContext->fPbufferContext ? shareContext->fPbufferContext->getGLRC()
: shareContext->fGlRenderContext;
}
- fPbufferContext = SkWGLPbufferContext::Create(fDeviceContext, 0, contextType, winShareContext);
+ fPbufferContext = SkWGLPbufferContext::Create(fDeviceContext, contextType, winShareContext);
HDC dc;
HGLRC glrc;