Con Kolivas
| Con Kolivas | |
|---|---|
| Residence | Melbourne, Australia |
| Occupation | Anaesthetist |
| Known for | Linux kernel development |
Con Kolivas is an Australian anaesthetist[1] who is known on the Internet for his programming work on the Linux kernel in his spare time. He has written patches for the kernel to improve its desktop performance, particularly reducing I/O impact. He has also written a benchmarking tool called ConTest[2] that can be used to compare the performance of different kernel versions.[3]
Kolivas is most notable for his work with CPU scheduling, most significantly his implementation of "fair scheduling," which inspired Ingo Molnár to develop his Completely Fair Scheduler, as a replacement for the earlier O(1) scheduler, crediting Kolivas in his announcement.[4] Kolivas developed several CPU schedulers such as the Staircase in 2004,[5] then Rotating Staircase Deadline (RSDL)[6] and subsequently Staircase Deadline (SD)[7] schedulers to address interactivity concerns of the Linux kernel with respect to desktop computing. Additionally, he has written a "swap prefetch" patch, which allows processes to respond quickly after the operating system has been idle for some time and their working sets have been swapped out.[8] Many of his experimental "-ck" patches, such as his prefetching and scheduling code, did not get merged with the official Linux kernel.
In 2007, Kolivas announced in an email that he would cease developing for the Linux kernel. Discussing his reasons in a 24 July online interview, he expressed frustration with aspects of the mainline kernel development process, which he felt did not give sufficient priority to desktop interactivity, in addition to hacking taking a toll on his health, work and family.[9][10] The catalyst for his decision in part may have been politics involving the adoption of Ingo Molnar's CFS scheduling algorithm versus his own. On the Linux Kernel Mailing List, it was suggested that Ingo Molnar would better maintain his source code after injection into the mainline kernel, which was a major reason for the adoption of CFS.
[edit] Brain Fuck Scheduler
On 31 August 2009, Kolivas posted a new scheduler called BFS (Brain Fuck Scheduler).[11] It is designed for desktop use and to be very simple (hence it may not scale to machines with many CPU cores well). Con Kolivas does not intend to get it merged into the mainline Linux.[12] He has since begun maintaining the -ck patch set again.
[edit] References
- ^ Anaesthesia Information Page by Kolivas
- ^ The homepage of contest
- ^ KernelTrap
- ^ Linux: The Completely Fair Scheduler | KernelTrap
- ^ The staircase scheduler [LWN.net]
- ^ The Rotating Staircase Deadline Scheduler [LWN.net]
- ^ LKML: Con Kolivas: [PATCH]Staircase scheduler - experimental
- ^ Swap prefetching [LWN.net]
- ^ Mills, Ashton (2007-07-24). "Why I quit: kernel developer Con Kolivas". apcmag.com. http://apcmag.com/why_i_quit_kernel_developer_con_kolivas.htm. Retrieved 2010-07-13.
- ^ corbet (2007-07-25). "Re: -mm merge plans for 2.6.23". lwn.net/Articles. http://lwn.net/Articles/242768/. Retrieved 2010-07-13.
- ^ Con Kolivas returns with a new scheduler [LWN.net]
- ^ BFS FAQ
[edit] External links
- Kolivas' personal website
- Kolivas' patches at kernel.org, main kernel repository
- Kolivas' FAQ for the BFS scheduler
- The "automated per tty task groups" patch, for desktop responsiveness
