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

Con Kolivas
2007-04-15T22:53:52Z

On Monday 16 April 2007 05:00, Jonathan Lundell wrote:
> On Apr 15, 2007, at 10:59 AM, Linus Torvalds wrote:
> > It's a really good thing, and it means that if somebody shows that
> > your
> > code is flawed in some way (by, for example, making a patch that
> > people
> > claim gets better behaviour or numbers), any *good* programmer that
> > actually cares about his code will obviously suddenly be very
> > motivated to
> > out-do the out-doer!
>
> "No one who cannot rejoice in the discovery of his own mistakes
> deserves to be called a scholar."

Lovely comment. I realise this is not truly directed at me but clearly in the
context it has been said people will assume it is directed my way, so while
we're all spinning lkml quality rhetoric, let me have a right of reply.

One thing I have never tried to do was to ignore bug reports. I'm forever
joking that I keep pulling code out of my arse to improve what I've done.
RSDL/SD was no exception; heck it had 40 iterations. The reason I could not
reply to bug report A with "Oh that is problem B so I'll fix it with code C"
was, as I've said many many times over, health related. I did indeed try to
fix many of them without spending hours replying to sometimes unpleasant
emails. If health wasn't an issue there might have been 1000 iterations of
SD.

There was only ever _one_ thing that I was absolutely steadfast on as a
concept that I refused to fix that people might claim was "a mistake I did
not rejoice in to be a scholar". That was that the _correct_ behaviour for a
scheduler is to be fair such that proportional slowdown with load is (using
that awful pun) a feature, not a bug. Now there are people who will still
disagree violently with me on that. SD attempted to be a fairness first
virtual-deadline design. If I failed on that front, then so be it (and at
least one person certainly has said in lovely warm fuzzy friendly
communication that I'm a global failure on all fronts with SD). But let me
point out now that Ingo's shiny new scheduler is a fairness-first
virtual-deadline design which will have proportional slowdown with load. So
it will have a very similar feature. I dare anyone to claim that proportional
slowdown with load is a bug, because I will no longer feel like I'm standing
alone with a BFG9000 trying to defend my standpoint. Others can take up the
post at last.

--
-ck