Robert Love, Preemptible Kernel Maintainer Interviewed

Tom F writes: "LinuxDevices did an interesting interview with Robert Love, the maintainer of the Linux preemptible kernel along with MontaVista. It is an exciting read and has Robert's usual wit and insight."

Comments

Re:low-latency patch

[steveha]

I have been following these two patches a bit, because I want my desktop to be as snappy and responsive as possible.

The current low-latency patches work by finding "hot spots" in the kernel code where something is taking a long time, and then putting in a hack to make the code yield. The good part is that you can get a really low-latency kernel; the bad part is that you have to touch the kernel code in hundreds of places, and the kernel code gets really ugly. I remember reading that Ingo Molnar, who wrote a giant low-latency patch that worked this way, agreed with Linus that his low-latency patch was just too ugly and huge and should not be included in the main source tree.

The preemption patch is comparatively small and elegant. It leverages the work that has already been done to make SMP work correctly. I'm using it on my Linux desktops, and I like it.

On one of the mailing lists, Linus said that he wants the Linux kernel to gain low latency the cleanest way: find all parts that are slow, and instead of hacking them to yield, re-write them so they are faster (but still clean code that is easy to understand). This is of course the ideal, but when will it be finished? The preemption patch is available now, and works now, and I am using it now.

steveha