If you're on a Linux system, sysprof is your best friend. First, make sure you've got the kernel development headers, and debugging information for the things you're trying to profile. On a Fedora system, that looks like:

% sudo yum -y install kernel-devel
% sudo debuginfo-install -y xorg-x11-server-Xorg xorg-x11-drv-savage

Then, build sysprof:

% git clone git://git.gnome.org/sysprof
% cd sysprof
% ./autogen.sh
% make
% sudo make install
% sudo sysprof &

Click "Start", do some stuff, click "Profile", and revel in the glorious CPU time accounting.

Note that sysprof is itself an X application, so you may want to run it forwarded to another display so it doesn't end up profiling its own animation.