Re: 2.2.0-pre[56] swap performance poor with > 1 thrashing task

Zlatko Calusic
1999-01-09T06:33:17Z

Dax Kelson <dkelson@inconnect.com> writes:

> On 7 Jan 1999, Zlatko Calusic wrote:
> >
> > 1) Swap performance in pre-5 is much worse compared to pre-4 in
> > *certain* circumstances. I'm using quite stupid and unintelligent
> > program to check for raw swap speed (attached below). With 64 MB of
> > RAM I usually run it as 'hogmem 100 3' and watch for result which is
> > recently around 6 MB/sec. But when I lately decided to start two
> > instances of it like "hogmem 50 3 & hogmem 50 3 &" in pre-4 I got 2 x
> > 2.5 MB/sec and in pre-5 it is only 2 x 1 MB/sec and disk is making
> > very weird and frightening sounds. My conclusion is that now (pre-5)
> > system behaves much poorer when we have more than one thrashing
> > task. *Please*, check this, it is a quite serious problem.
>
> I just tried this on 2.2.0-pre6 PentiumII 412Mhz, 128MB SDRAM, one IDE
> disk (/ & swap).
>
> ./hogmem 200 3
> Memory speed: 9.01 MB/sec
>
> ./hogmem 100 3 & ./hogmem 100 3
> Memory speed: 0.96 MB/sec
> Memory speed: 0.96 MB/sec
>

I have a fix for this, together with a great improvement in swapping
speed that I'll be sending in few moments, after some final testing.

pre6 is VERY good, and with my changes, we will have fastest MM ever!
--
Zlatko