The Linux 2.6.31 kernel is still under active development until it is released later this quarter, but the merge window is closed and most of the work going on is to address bugs and other regressions within this massive code-base. Some of the key additions to the Linux 2.6.31 kernel include many graphics-related advancements (merging of the TTM memory manager, Radeon kernel mode-setting, Intel DisplayPort, etc), an ALSA driver for the Creative X-Fi, initial USB 3.0 support, file-system improvements, and much more. To see how the general system performance has been impacted by the new Linux kernel that is in development, we have a few benchmarks today.
This round of testing is quite simple as we simply tested the Linux 2.6.29, 2.6.30, and 2.6.31-rc2 kernels (from the Ubuntu mainline kernel PPA for AMD64) on one of our test systems with the Phoronix Test Suite (http://www.phoronix-test-suite.com/). This system consisted of an Intel Core 2 Duo E8400 clocked at 4.00GHz, an ASUS P5E64 WS Professional motherboard, 2GB of DDR3 memory, a 160GB Western Digital WD1600JS-00M Serial ATA 2.0 hard drive, and a NVIDIA GeForce 9800GT graphics card. On the software side this system was running Ubuntu 9.04 (x86_64) with GNOME 2.26.1, X Server 1.6.0, GCC 4.3.3, and an EXT4 file-system.
The tests where we have published the results for are with Parallel BZIP2 Compression, Apache, Bwfirt, Threaded I/O Tester, PostMark, Dbench, dcraw, and PostgreSQL. We had run more tests, of course, but in a majority of the other test profiles there were little differences with the newest Linux 2.6.31 kernel. We had run these tests with the 64-bit mainline kernel packages for Linux 2.6.29, Linux 2.6.30, and the Linux 2.6.31-rc2 kernel, which was the latest at the time of testing. We will have more benchmarks coming as the Linux 2.6.31 kernel matures and there is more information to report on.