"Long story short, in tracking down this performance
regression we have finally devised a way to autonomously locate
performance regressions within the Linux kernel and potentially any
Git-based project for that matter. Here are a few details.
"For some background information on the test that led to this
work, the PostgreSQL performance under the Linux 2.6.32-rc1 through
the Linux 2.6.32-rc5 (and still in Git master) is in shambles when
compared to earlier kernels (tested Linux 2.6.30 and 2.6.31 for
comparison). This regression was found using the same kernel
configuration with the default options on a clean Ubuntu 9.10
installation. To ensure this wasn't an isolated incident, first
this regression was confirmed on an entirely different system -- a
dual AMD Opteron system compared to an Intel Atom "nettop"