[Mesa-users] Very low framerate when recording desktop content in Weston using mesa git on Radeon 5770 (glReadPixels slow path?)

[Rune Kjær Svendsen]

Hello list

I'm having problems recording the desktop content using the Weston
compositor's built-in recording function. When I start a recording and do
something that changes a lot of screen content (like zooming in on the
desktop, for example), I get around 0.5 FPS. Using sysprof, I can see that
~98% of CPU is used in the function unpack_XRGB8888(). krh has told me this
is caused by glReadPixels going through a slowpath. I have a Radeon HD 5770
GPU and I'm using mesa git (I've tried the mesa version in the Ubuntu 12.10
repos, and the xorg-edgers PPA, same result).

Does anyone know what the issue could be, or how to debug the problem
further?

/Rune
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