Re: Linus 2.6.23-rc1

Linus Torvalds
2007-07-28T17:51:53Z

On Sat, 28 Jul 2007, Kasper Sandberg wrote:
>
> First off, i've personally run tests on many more machines than my own,
> i've had lots of people try on their machines, and i've seen totally
> unrelated posts to lkml, plus i've seen the experiences people are
> writing about on IRC. Frankly, im not just thinking of myself.

Ok, good. Has anybody tried to figure out why 3D games seem to be such a
special case?

I know Ingo looked at it, and seemed to think that he found and fixed
something. But it sounds like it's worth a lot more discussion.

> Okay, i wasnt going to ask, but ill do it anyway, did you even read the
> threads about SD?

I don't _ever_ go on specialty mailing lists. I don't read -mm, and I
don't read the -fs mailing lists. I don't think they are interesting.

And I tried to explain why: people who concentrate on one thing tend to
become this self-selecting group that never looks at anything else, and
then rejects outside input from people who hadn't become part of the "mind
meld".

That's what I think I saw - I saw the reactions from where external people
were talking and cc'ing me.

And yes, it's quite possible that I also got a very one-sided picture of
it. I'm not disputing that. Con was also ill for a rather critical period,
which was certainly not helping it all.

> Con was extremely polite to everyone, and he did work
> with a multitude of people, you seem to be totally deadlocked into the
> ONE incident with a person that was unhappy with SD, simply for being a
> fair scheduler.

Hey, maybe that one incident just ended up being a rather big portion of
what I saw. Too bad. That said, the end result (Con's public gripes about
other kernel developers) mostly reinforced my opinion that I did the right
choice.

But maybe you can show a better side of it all. I don't think _any_
scheduler is perfect, and almost all of the time, the RightAnswer(tm) ends
up being not "one or the other", but "somewhere in between".

It's not like we've come to the end of the road: the baseline has just
improved. If you guys can show that SD actually is better at some loads,
without penalizing others, we can (and will) revisit this issue.

So what you should take away from this is that: from what I saw over the
last couple of months, it really wasn't much of a decision. The difference
in how Ingo and Con reacted to peoples reports was pretty stark. And no, I
haven't followed the ck mailing list, and so yes, I obviously did get just
a part of the picture, but the part I got was pretty damn unambiguous.

But at the same time, no technical decision is ever written in stone. It's
all a balancing act. I've replaced the scheduler before, I'm 100% sure
we'll replace it again. Schedulers are actually not at all that important
in the end: they are a very very small detail in the kernel.

Linus