simple compile-time-selectable profiling points
Submitted by Simon McVittie
A number of GNOME modules have access()-based "profiling points" which can be used in conjunction with strace to get an idea of how long an application spends, for instance, blocking on I/O. While working on Bug #687362 I've found it useful to add some of these to GLib and GIO.
I realise that in general, GNOME developers are more in favour of systemtap - perhaps because many GNOME developers use Fedora, which has a kernel with the utrace patchset necessary to make userland systemtap points useful...