For handling a 8GB write of 4Kb block sizes using IOzone, EXT4 and XFS were on top. EXT4 was about 9% faster than Btrfs for this write test.
For a 8GB read, EXT4 continued being on top. This time, EXT4 was about 13% faster than Btrfs in this simple benchmark. EXT4 was faster than XFS by about 6%.
The Threaded I/O Tester results were not particularly interesting.