While getting my daily Chris Sells fix I got pointed to this blog written by Rico Mariani.
In these two posts here and here, Rico breaks down the process of looking at the performance details of a managed process and drilling down to the possible reasons and suggests fixes in each case. This looks like a great starting point when trying to track down code related performance issues. Rico's blog looks like it's chock-full of this stuff.
Thanks to Chris for the pointer to Rico's blog. Subscribed.