Hmm, gprof seems to behave weird on my mac, I can't really get something useful out of it. When I attach Shark (a Mac OS X sampling profiler), I get the profile of http://el-tramo.be/tmp/psi_profile.png . It seems a lot of time is spent in entryList(). Does this make sense? The other 50% spent in Psi is distributed, so nothing weird there. Remko