X-Server 1.5.0 very sluggish
最近升到 xorg 1.5.0，某些操作 (terminal 快速更新) 會使 xserver 佔用非常多 cpu，看來是這個問題
Working on it ... right now it looks like:
XShm pixmaps got accidentally reenabled in the course of
Someone (maybe GTK, having tracked it down yet) is taking advantage
of that by creating a shared pixmap and using it as the source for
a composite operation.
That is not handled well in EXA and triggers migration of the
destination back to system memory. ()) One of the many cases where we'd be better off creating temporaries
in video memory to avoid migration.