With Emacs 24.3 (and possibly earlier versions) under OS X 10.9 there is a nasty problem that causes
distnoted, the OS X distributed notifications daemon, to periodically suck up processor resources and basically tie up the machine. Sometimes it recovers on its own, sometimes you have to restart Emacs. That is particularly apt to happen after waking up from sleep mode.
The problem is fixed in the 24.4 release and I've been ignoring it while I waited for the new release. The other day, though, I ran out of patience and hunted up a patch I'd seen for it some time ago. If you build Emacs from source, it's trivial to apply it: just follow the instructions in the patch commentary1.
After applying the patch and rebuilding, everything worked normally again and I haven't had anymore runaway
distnoted problems. Actually, the whole system seems snappier after I installed the patch. That's not too surprising given that Emacs is always running on my machines. If you're running Emacs on OS X 10.9, you may want to rebuild Emacs with the patch. As long as you have a C development environment, that's easy. I don't know if Homebrew and the other package systems have applied the patch or not.
For some reason that I've long forgotten, I don't have to do the
step. If you get a fatal error on the
step, just start over but omit the