Re: [ck] Re: [Announce] [patch] Modular Scheduler Core and Completely Fair Scheduler [CFS]

Nick Piggin
2007-04-16T06:27:08Z

On Mon, Apr 16, 2007 at 03:57:54PM +1000, Matthew Hawkins wrote:
> On 4/16/07, Nick Piggin <npiggin@suse.de> wrote:
> >
> >So, on to something productive, we have 3 candidates for a new scheduler
> >so
> >far. How do we decide which way to go? (and yes, I still think switchable
> >schedulers is wrong and a copout)
>
>
> I'm with you on that one. It sounds good as a concept however there's
> various kernel structures etc that simply cannot be altered at runtime,
> which throws away the only advantage I can see of plugsched - a test/debug
> framework.
>
> I think the best way is for those working on this stuff to keep producing
> their separate patches against mainline and people being encouraged to
> test. THEN
> (and here comes the fun part) subsystem maintainers have to be prepared to
> accept code that is not their own or that of their IRC buddies. I'm
> noticing this disturbing trend that Linux kernel development is becoming
> more and more like BSD where only the elite few ever get anywhere. Con
> Kolivas, having a medical not CS degree, bruises the egos of those with CS
> degrees when he comes up with fairly clean, working, and widely-tested
> implementations of things like the staircase scheduler, R(SD)L, SCHED_ISO,
> swap prefetch, etc. when they can't. We should be encouraging guys like

The thing is, it is really hard for anybody to change anything in page
reclaim or CPU scheduler. A few people saying a change is good for them
doesn't really mean anything because of the huge amount of diversity in
usages.

I've got my own CPU scheduler for 4 years and I and a few others think
it is better than mainline. I've tried to make many many VM changes
that haven't gone in.

Add to that, I don't actually know or care what sort of education most
kernel hackers have. I do know at least one of the more brilliant ones
does not have a CS degree, and I was able to get quite a few things in
before I had a degree (eg. rewrote IO scheduler and multiprocessor
CPU scheduler).

> It's all about the patches, baby

I don't know what would give anyone the idea that it isn't... patches
and numbers.

Nick