Linux 3.18 File-System Performance Minimally Changed But Possible Regressions

First up is the common Flexible IO Tester.

When carrying out random reads with FIO using POSIX AIO, there was a clear drop in performance across all four tested file-systems. EXT4, Btrfs, XFS, and F2FS all saw the speed of random reads reduced when using Linux 3.18 Git compared to Linux 3.17, which means it could be a regression in the block layer or other area of the kernel.

The random write performance went unchanged between Linux 3.17 and 3.18 Git for the four file-systems.

With sequential reads in FIO there was also a reduction in performance when using Linux 3.18 with your choice of EXT4, Btrfs, XFS, and F2FS.

The sequential write performance also shows the disk write speed dropping across all four file-systems on the Serial ATA 3.0 SSD with the Linux 3.18 kernel.