I meant the file root. A stat call is made for every directory in the path. The fewer directories, the fewer calls. Dont know how much you will gain by this tip though. Please try it and post your results...
I also know that Yahoo is using a patched version of PHP to speed up stat calls on FreeBSD. Basically they remove many of the "un needed" stat calls in their case. I think Rasmus Lerdorf also has posted this patch on the PHP devel list some time ago.
This patch should improve the performance noticeably on FreeBSD.
Re Referenced Thread: Now that I have moved to new hardware the performance is very impressive. Maybe it would be quicker in Linux but I can't say I would notice it.