This thread and patch are silly, but running out of entropy can be a real performance problem sometimes. I've seen it on embedded Linux systems that I've set up to be headless servers. After turning off lots of device drivers, I noticed that SSH was incredibly slow sometimes. The problem was a lack of entropy, causing reads to /dev/random to block. Like in the article, the quick hack is to redirect /dev/urandom to /dev/random, but that isn't a real fix because of the security implications. The right fix was digging through the available devices and figuring out where entropy could be legitimately captured.