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Old 09-12-07, 10:17 AM   #2
NVIDIA Corporation
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Join Date: Mar 2005
Posts: 2,487
Default Re: Window resizing _very_ slow with compiz

Window resizing with Composite is slow because every time the window is resized, the server creates a new pixmap (which starts out in system memory by default) and then copies the contents of the old pixmap into it, which does a readback from video memory. Then, when compiz creates a texture for that pixmap, that uploads it to video memory again. This is clearly inefficient. You can improve resizing performance considerably by setting InitialPixmapPlacement to 2 so that all that's required is a fast vidmem-to-vidmem blit. However, most of the time the copy is useless anyway because the application will repaint the entire window in response to a resize.
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