With the initial create test in the CompileBench test profile, the EXT4 file-system beat out EXT3 and Btrfs in both the Karmic and Lucid releases of Ubuntu. The EXT4 file-system was nearly twice as fast as EXT3 in Ubuntu 9.10 and with Ubuntu 10.04, it is looking like it will definitely be over twice as fast in this test. Btrfs was running right behind EXT4 in the Ubuntu 9.10 release, but it regressed slightly and could not match the EXT4 improvements found in this test with Lucid.
EXT4 continued to run much stronger than EXT3 with the compile test in CompileBench, but in both the 9.10 and 10.04 versions of Ubuntu the Btrfs file-system took the gold. In fact, on this Samsung netbook the Btrfs file-system on Ubuntu 10.04 ran over twice as fast as EXT4. There is a very significant boost here for the Btrfs file-system in the Linux 2.6.32 kernel.
EXT3 appears to have a nasty regression with the "read compiled tree" in CompileBench between Karmic and Lucid while the EXT4 file-system did the best and its numbers were stable between the Ubuntu releases tested. The Btrfs file-system was running a few megabytes per second slower than the EXT4 file-system and its numbers were also level between 9.10 and 10.04.
With the 4GB write test in IOzone, EXT3 was no match for either EXT4 or Btrfs. EXT4 was the fastest file-system with the IOzone 4GB write tests on Ubuntu 9.10, but with our Lucid Lynx snapshot the Btrfs pulled a slight lead over the evolutionary EXT4 file-system thanks to performance optimizations.