SwapChain->Present is called with sync on WebRender + ANGLE. But MLGSwapChainD3D11::Present() and CompositorD3D11::Present() call SwapChain->Present is called without sync. It seems better to call SwapChain->Present without sync from performance point of view. I quickly tested the "without sync", fps became better and more stable at http://learningwebgl.com/lessons/lesson03/index.html on Lenovo P50(Win).

Comment on attachment 8929958 [details] [diff] [review] patch - Set SwapInterval to 0 with ANGLE Review of attachment 8929958 [details] [diff] [review]: ----------------------------------------------------------------- It's worth noting that this would only allow for screen tearing with EGL_RENDER_BUFFER=EGL_SINGLE_BUFFER. ::: gfx/gl/GLContextProviderEGL.cpp @@ +217,5 @@ > > gl->MakeCurrent(); > gl->SetIsDoubleBuffered(doubleBuffered); > + if (aWebRender && sEGLLibrary.IsANGLE()) { > + sEGLLibrary.fSwapInterval(EGL_DISPLAY(), 0); MOZ_ASSERT(doubleBuffered); We really don't want to set this to zero if our EGLSurface is single-buffered. (GLES nominally doesn't support EGL_RENDER_BUFFER=EGL_SINGLE_BUFFER, and ANGLE is GLES)

Pushed by sikeda@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/bb6ea78f779e Set SwapInterval to 0 with ANGLE r=jgilbert