Open Radar

 
Chrome uses a NSOpenGLContext drawing to an NSView to draw its content. On a Retina Macbook Pro, when using the integrated GPU, animated pages will sometimes shake and stutter.

I've narrowed this down to a system synchronization issue. In particular, if I add glFinish before calling CGLFlushDrawable/flushBuffer, then the correct contents appear.

This issue is new on 10.9, and only happens when using the Intel GPU (it goes away when switched to the discrete GPU). I have only seen this on the retina Macbook Pro.

The issue reproduces more easily with lots of GL windows open. I've attached a program to help in this.

Steps to Reproduce:
1. Install Google Chrome
2. Compile and run the attached lots_of_gl_windows.mm (instructions are in the source file).
    - This is not strictly necessary, but make it will make the repro happen more often.
3. Run Chrome from the command line with the flag --disable-gpu-driver-bug-workarounds (so, the line "/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --disable-gpu-driver-bug-workarounds" will do it).
4. Open 5 Chrome windows, and navigate to http://www.webkit.org/blog-files/3d-transforms/poster-circle.html in each of them
5. Make sure that the Chrome windows are on top of the other OpenGL windows (cycles through the windows a few times)

Expected Results:
The animations should be smooth (if perhaps slow).

Actual Results:
The animations shudder and flicker as the front and back buffers are swapped inappropriately.

Version:
OS X 10.9, Build 13A603