I run mpd on debian on "igor", an NSLU2 -- a very low-power \~266MHz armel machine, with no FPU and a scanty 32MiB of RAM. This serves nicely to feed my stereo with music that is controllable from anywhere on my LAN. When playing music and talking to a single mpd client, the machine is about 50% idle.
However, during a recent upgrade, something wanted to pull in pulseaudio, which in turn wanted to pull in libasound2-plugins, and i distractedly (foolishly) let it. With that package installed, after an mpd restart, the CPU was completely thrashed (100% utilization) and music only played in stutters of 1 second interrupted by a couple seconds of silence. igor was unusable for its intended purpose.
Getting rid of pulseaudio was my first attempt to fix the stuttering, but the problem remained even after pulse was all gone and mpd was restarted.
Then i did a little search of which packages had been freshly installed in the recent run:
grep ' install .* <none> ' /var/log/dpkg.log
and used that to pick out the offending package.
After purging libasound2-plugins and restarting mpd, the igor is back in action.
Lesson learned: on low-overhead machines, don't allow apt to install recommends!
echo 'APT::Install-Recommends "0";' >> /etc/apt/apt.conf
And it should go without saying, but sometimes i get sloppy: i need to pay closer attention during an "apt-get dist-upgrade"