Created attachment 121247 [details]
strace -p output of compiz when it slows down the system.
compiz slows the system down with multiple: recvmsg(5, 0xbf8ca5b4, 0) = -1 EAGAIN (Resource temporarily unavailable)
Sometimes hangs the system for hours. (May be also bug 92523)
I have a strace -p of compiz attached.
I have not been able to determine what FD=5 is.
And there was about 500 MB of swap still available, so I don't think it was a memory issue.
Compiz bugs are tracked at https://launchpad.net/compiz, not here.