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

William Lee Irwin III
2007-04-15T23:39:44Z

On Sun, Apr 15, 2007 at 10:48:24PM +0200, Ingo Molnar wrote:
> 2) plugsched did not allow on the fly selection of schedulers, nor did
> it allow a per CPU selection of schedulers. IO schedulers you can
> change per disk, on the fly, making them much more useful in
> practice. Also, IO schedulers (while definitely not being slow!) are
> alot less performance sensitive than CPU schedulers.

One of the reasons I never posted my own code is that it never met its
own design goals, which absolutely included switching on the fly. I
think Peter Williams may have done something about that. It was my hope
to be able to do insmod sched_foo.ko until it became clear that the
effort it was intended to assist wasn't going to get even the limited
hardware access required, at which point I largely stopped working on
it.

On Sun, Apr 15, 2007 at 10:48:24PM +0200, Ingo Molnar wrote:
> 3) I/O schedulers are pretty damn clean code, and plugsched, at least
> the last version i saw of it, didnt come even close.

I'm not sure what happened there. It wasn't a big enough patch to take
hits in this area due to getting overwhelmed by the programming burden
like some other efforts of mine. Maybe things started getting ugly once
on-the-fly switching entered the picture. My guess is that Peter Williams
will have to chime in here, since things have diverged enough from my
one-time contribution 4 years ago.

-- wli