Re: [BUG] /proc/<pid>/stat access stalls badly for swapping process, 2.4.0-test10

From: Mike Galbraith (mikeg@wen-online.de)
Date: Sat Nov 04 2000 - 00:43:17 EST


On Fri, 3 Nov 2000, Jens Axboe wrote:

> On Fri, Nov 03 2000, Mike Galbraith wrote:
> > > I very much agree. Kflushd is still hungry for free write
> > > bandwidth here.
> >
> > In the LKML tradition of code talks and silly opinions walk...
> >
> > Attached is a diagnostic patch which gets kflushd under control,
> > and takes make -j30 bzImage build times down from 12 minutes to
> > 9 here. I have no more massive context switching on write, and
> > copies seem to go a lot quicker to boot. (that may be because
> > some of my failures were really _really_ horrible)
> >
> > Comments are very welcome. I haven't had problems with this yet,
> > but it's early so... This patch isn't supposed to be pretty either
> > (hw techs don't do pretty;) it's only supposed to say 'Huston...'
> > so be sure to grab a barfbag before you take a look.
>
> Super, looks pretty good from here. I'll give it a go when I get back.
> In addition, here's a small patch that disables the read stealing
> of requests from the write list -- does that improve behaviour
> when we are busy flushing?

Yes. I've done this a bit differently here, and have had good
results. I only disable stealing when I need flush throughput.

Now that the box isn't biting off more than it can chew quite
as often, I'll try this again. I'm pretty darn sure that I can
get more throughput, but :> I've learned that getting too much
can do really OOGLY things. (turns box into single user single
tasking streaming IO monster from hell)

        -Mike

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