The CompileBench performance was the same on the tested kernels / file-systems except for XFS there was a performance drop going from a 110MB/s average to now just 91MB/s.
With another CompileBench task, the EXT4 performance had dropped from a 139MB/s average to 127MB/s while F2FS had also regressed.
Lastly, with the PostMark mail server benchmark the performance for EXT4, Btrfs, F2FS, and XFS file-systems all tested slower on the Linux 3.13 Git kernel for this system backed by an OCZ solid-state drive and Intel Core i5 Ivy Bridge processor.
At the moment we don't know the cause of why for several different disk workloads the file-system performance is slower on the Linux 3.13 development kernel. While Btrfs, EXT4, XFS, and F2FS were all affected negatively in multiple test cases, the file-system that appeared to regress the most for the greatest number of tests was the XFS file-system. Similar to the many past Linux kernel regressions we have found at Phoronix, we may end up bisecting the regression if no kernel pulls land in the next few days that happen to coincidentally correct the issue and also pending interest from Phoronix readers with any support contributions to warrant carrying out the timely task. Regardless, hopefully the issue(s) will be addressed in time for the final Linux 3.13 kernel release.