When starting the file-system tests with AIO-Stress, we saw right away that the EXT4 performance dropped dramatically. The XFS file-system performance was also down significantly. Maintaining its performance level was Btrfs and the Flash-Friendly File-System performance was only minimally degraded by last week's Linux 3.13 kernel. The fallout from the Linux 3.13 kernel in this test wasn't uniform and Btrfs actually was trying to rise in speed.
With the FS-Mark file-system benchmarks we see generally the file-systems losing ground on Linux 3.13 by a small fraction. Having the biggest hit from the Linux 3.13 kernel is the XFS and EXT4 file-systems. In some cases the XFS performance was halved.