Has anyone gotten performance gains on account of profile directed feedback optimization. I used gcc-3.4.3 and tried using profile directed feedback. This is what I did 1. Compiled the program using -fprofile-generate. I used this flag both in the compile flags and as part of the link flags. I also had to use libgcov.a during the link phase otherwise it would die looking for gcov functions. 2. Ran a representative work-load 3. Followed (1) except that instead of -fprofile-generate used -fprofile-use I had to drop the "-fprofile-use" on 2 files as they had corrupted profile data. So far so good. When I ran the profile directed feedback optimized executable, the performance was 20% slower. Anyone has experience with PDF they can share and point out what I am doing wrong? Thanks -girish
