EXT4 & Btrfs Regressions In Linux 2.6.36
Written by Michael Larabel in Software on 8 September 2010. Page 3 of 3. Add A Comment

With Compile Bench we have a look at where the performance fell between the Linux 2.6.34 and 2.6.35 kernels, but rather than being corrected in 2.6.36, the performance actually falls further. The EXT4 disk performance with Compile Bench barely changed between 2.6.35 and 2.6.36-rc3, but the Btrfs performance dropped by another 25%. Between the Linux 2.6.34 and 2.6.36-rc3 kernel releases the performance of Btrfs on the solid-state drive has dropped by nearly 40%.

The Flexible IO Tester performance only regressed slightly with the three tested kernels on the specified hardware.

With the Threaded I/O Tester when doing eight threads of 32MB random writes, the EXT4 file-system performance was maintained between Linux 2.6.34 and 2.6.36. Btrfs meanwhile dropped by 14% between Linux 2.6.34 and 2.6.35 and then between 2.6.35 and 2.6.36-rc3 it has dropped by an additional 11%.

These results are certainly a shock and not what we were expecting to see when testing the premiere Linux file-systems atop the latest kernel code that will be released as stable in just a month or two. The good news though is that these Linux file-system regressions do not appear across the board, but for example with our Intel Atom system with an HDD that is benchmarking the very latest kernel code on a daily basis at kernel-tracker.phoromatic.com don't suffer from these massive performance blows. Our investigation shall continue.


About The Author
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Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter or contacted via MichaelLarabel.com.


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