1374710 - GLBlitHelper should cache the various shaders

Status: NEW

(Core :: Graphics, enhancement, P5)

Description

[Jean-Yves Avenard [:jya]]

Whenever GLBlitHelper::BlitImageToFramebuffer is called, it will call GLBlitHelper::InitTexQuadProgram.

This code will compile the various shaders required for the conversion.

This is done every single time BlitImageToFramebuffer is called.

I haven't profiled that code, however, it's not hard to imagine that the shaders compilation take a significant amount of time...

This work should be cached and reuse when/if possible.

Comment 1

[Jean-Yves Avenard [:jya]]

Actually, running a profiler on https://people-mozilla.org/~jyavenard/webgl-videotest/webgl-videotest.html?fast=true (after disabling the HW decoder) as FastPath only works with YUV software images. and e10s off

The majority of time is spent in:
Function Name	Total CPU (%)	Self CPU (%)	Total CPU (ms)	Self CPU (ms)	Module
 + nsDisplayList::PaintRoot	16.90 %	0.00 %	1533	0	xul.dll

Only 5% in:
Function Name	Total CPU (%)	Self CPU (%)	Total CPU (ms)	Self CPU (ms)	Module
 + mozilla::dom::WebGLRenderingContextBinding::texImage2D	5.09 %	0.00 %	462	0	xul.dll

of that, it's almost exclusively mozilla::gl::GLBlitHelper::BlitImageToFramebuffer	4.85 %

InitTexQuadProgram is only 0.02%

So this bug is likely irrelevant in the grand scheme of things.