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blu / hello-chromeos-gles2

"Hello GLES2" on ChromeOS, self-hosted style
MIT License
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R70 performance issues #3

Open blu opened 6 years ago

blu commented 6 years ago

  1. The new alpha-blended + blurred shelf overlay in R70 kills the performance of underlying apps when blended on top of a 60fsp GLES app. R70 is the first revision where the shelf overlay is not just alpha-blended but is also blurred, so apparently this takes plenty of resources from the underlying app. As a workaround hide the shelf overlay when running 60fps GLES apps.

  2. The fence-sync scheme on redraw performs poorly under R70, resulting in frequent framerate stuttering; scheme disabled as of commit 55b1481.

blu commented 6 years ago

Update: further investigation of redraw shows the framerate to be sensitive to both the fence sync mechanism as well as to a simple GLES flush at redraw. Best results observed with a sync-less, flush-less redraw.

At the same time, Task Manager does not show any significant difference in the CPU utilization of GPU Processes between R69 and R70 -- 32-38% during sphere app.

blu commented 6 years ago

Update on point 1 above: as of R70.0.3538.41 Beta the shelf overlay has been reverted to alpha-blended-only. Alas, GLES apps slowdown with the shelf overlay on top is still noticeable, albeait to a smaller degree.