Re: [PATCH] CFQ scheduler, #2

Mike Galbraith
2003-02-15T11:53:11Z

At 09:49 AM 2/15/2003 -0200, Rik van Riel wrote:
>On Sat, 15 Feb 2003, Mike Galbraith wrote:
>
> > >Judging from your log, it ends up stalling kswapd and
> > >dramatically increases the number of times that normal
> > >processes need to go into the pageout code.
> > >
> > >If this provides an anti-thrashing benefit, something's
> > >wrong with the VM in 2.5 ;)
> >
> > Which number are you looking at?
>
>pgscan 2751953 5328260 <== ? hmm
>
>kswapd_steal 380282 522126
>pageoutrun 1107 1956
>allocstall 3472 1238
>
>- we scan far less pages
>- kswapd reclaims less pages
>- we go into the pageout code less often
>- allocations stall more often for a lack of free memory

I would interpret that differently. I would say we scan less because we
don't need to scan as much, kswapd reclaims less for the same reason, and
ditto for pageout ;-) The reduction in scans does seem _way_ high though...

wrt allocstall, I bet if I do a few runs, I'll see mucho variance there
(could be wrong.. hunch)

-Mke