Five Years Of Linux Kernel Benchmarks: 2.6.12 Through 2.6.37

The Dhrystone 2 performance was not interesting in terms of kernel changes causing a performance impact.

Looking at the time to transfer 10GB via the TCP network loop-back interface was interesting. The performance actually regressed a fair amount within the Linux kernel over the past few releases. Google made some improvements in the Linux 2.6.36 kernel to the networking stack, which may partially attribute the improvement we noted in this release (from 55 seconds down to 44 seconds), but with the Linux 2.6.37 kernel (44 seconds) it's still noticeably behind of where this test was running in the Linux 2.6.12 kernel (26 seconds) and in the Linux 2.6.20 kernel (13 seconds) where it performed the best.

Due to file-system changes or another sub-system, (this is another test where the results will likely be bisected), the time it took to compile Apache dropped along the way and is doing rather well in recent versions of the Linux kernel.

The Apache benchmark is the start of our file-system-focused benchmarks, which have always proved to be particularly interesting when comparing versions of the Linux kernel. The Apache web-serving performance was impacted greatly between Linux kernel releases as the EXT3 file-system was altered and other changes in the Linux kernel. With the Linux 2.6.12 kernel, Fedora Core 4 with the Apache server was handling 8290 requests per second while it peaked in the Linux 2.6.27 kernel at an impressive 17132 requests per second and has receded in almost every release since. The stable Linux 2.6.36 kernel was handling 7014 requests per second on average and with the latest Linux 2.6.37 unstable kernel it looks to be up to about 7841 requests per second. While we know the EXT4 performance and Btrfs performance is near-constantly changing as both file-systems mature and new features added to improve data integrity and introduce other capabilities, it is interesting the mature EXT3 file-system continues to churn as well.