My entire machine OSX Lion machine slows down while XCode 4.4 is indexing. The CPU is less than 10% busy, I've got over 500 MB free memory, plenty of disk space, disk IO rate is not high, network activity is not high. Indexing just a few files can take minutes and builds are extremely slow. While this is going on, even loading a new web page in Chrome can be slow.
Knowing how to fix it would be great, but more fundamentally how can I measure what is actually going slowly? What metrics should I be looking at? Nothing in Activity Monitor, iostat, top, or sar betray anything about what's going on to me. Even getting a man page is interminable.