Early Linux 2.6.31 Kernel Benchmarks
Where we see the biggest change in performance with today's Linux kernel testing was with the Threaded I/O Tester. With the 64MB write testing with 32 threads, the latency had regressed a fair amount between the 2.6.29 and 2.6.30 kernels, but with the Linux 2.6.31-rc2 kernel on this EXT4 file-system the latency continued to rise much higher.
It was just not the write performance that experienced higher latency, but the read performance was much worse -- nearly six times higher between Linux 2.6.30 and 2.6.31-rc2.
Continuing with the disk benchmarks, NetApp's PostMark test had not sustained as many disk transactions per second with the 2.6.31-rc2 kernel as it did with Linux 2.6.30, but still it was well ahead of the performance found in the Linux 2.6.29 kernel.