Con Kolivas [interview] continues to maintain the performance oriented -ck patchset that he started in early 2004 [story], "this patchset is designed to improve system responsiveness and interactivity. It is configurable to any workload but the default -ck patch is aimed at the desktop and -cks is available with more emphasis on serverspace." In Con's latest release, 2.6.21-ck1, he notes that he has updated the patchset to include his improved SD cpu scheduler [story], "the staircase-deadline cpu scheduler has replaced the old staircase design in this version."
Con goes on to explain, "the staircase-deadline cpu scheduler can be set in either purely forward-looking mode for absolutely rigid fairness and cpu distribution according to nice level, or it can allow a small per-process history to smooth out cpu usage perturbations common in interactive tasks by enabling this sysctl. While small fairness issues can arise with this enabled, overall fairness is usually still strongly maintained and starvation is never possible. Enabling this can significantly smooth out 3d graphics and games." Swap prefetch [story] is also among the patches included in the -ck patchset.
Con Kolivas, a practicing doctor in Australia, has written a benchmarking tool called ConTest which has proven to be tremendously useful to kernel developers, having been designed to compare the performance of different versions of the Linux kernel. He was kind enough to speak with us, explaining how he got started on this project, what makes his benchmark unique, and how to interpret the resulting output. Comparing the 2.5 development kernel to the 2.4 stable kernel, Con says, "a good 2.5 kernel (and that's not all of them) feels faster than 2.4 in most ways and this bodes well for 2.6." The interesting results from his frequent benchmarks back up this statement.
Con also describes his high performance patchset for the 2.4 stable kernel, currently at version 2.4.19-ck9. This patchset adds a number of performance boosting patches ideal for a desktop environment, such as the O(1) scheduler, kernel preemption, low latency and compressed caching. Read on for the full interview...
Con Kolivas, maintainer of the high performance -ck patchsets [earlier story], contributed some interesting benchmark results that help compare the performance of several Linux kernels under varying loads.
Con Kolivas has been maintaining an excellent set of kernel patches " designed to improve system responsiveness, with emphasis on desktop pcs." The latest patches are against the stable 2.4.19 kernel, adding the O(1) scheduler, batch scheduling, kernel preemption, low latency and Andrea Arcangeli's latest -aa VM improvements. You can optionally swap the -aa VM for Rik van Riel's [earlier interview] -rmap VM, as included in Alan Cox's [earlier interview] 2.4 -ac branch.