With the Linux 3.18 development settling down, here's our usual benchmarks of the new kernel when comparing the file-system performance against the previous stable version (Linux 3.17) for EXT4, F2FS, XFS, and Btrfs.
As usual are the benchmarks between Linux 3.17 (stable) and Linux 3.18 (Git) when testing the four most popular Linux file-systems with their stock mount options on a solid-state drive. The hardware for this comparison was with the Intel Core i7 5960X Haswell-E system with a 240GB OCZ Vertex 3 used as the SSD for the file-system/kernel benchmarking. Ubuntu 14.10 x86_64 was running on the host with the 3.17 and 3.18 kernels being obtained from the Ubuntu Mainline Kernel PPA.
All of the Linux disk benchmarking was facilitated using the open-source Phoronix Test Suite open-source automated benchmarking software.
For those not keeping up with the 3.18 development, see my Linux 3.18 feature overview that also covers the file-system changes of this new kernel.