Comment 30 for bug 1293384

OK,

I did som investigation, and it seems like even for the slightest change in a window, like a cursor blink, compiz performs a fullscreen swapbuffer, and in the case of multiple monitors, compiz performs a swapbuffer that spans all the monitors.

I tried to install ccsm and disable all tweaks that could trigger this behaviour and revert to use GLX_MESA_copy_sub_buffer, but that didn't help much. Except if you start on a low resolution and change resolution to something higher. THEN compiz suddenly changes update and performs updates that are not quite that large. The only drawback is that those updates seem to cover also a number of unrelated areas that are not updated.

Now needless to say this becomes very suboptimal in remoted virtual environments, and also it appears very suboptimal if llvmpipe is used. Not to mention the combination of those two...