Re: severe slowdown with 2.4 series w/heavy disk access

[Paul Boley]

Alan Cox wrote:
> 
> >              total       used       free     shared    buffers
> > cached
> > Mem:        417472     412192       5280          0      20632
> > 315680
> 
> Thyose values dont show any problems. In fact your machine seems to think it
> had a ton of free memory to waste and has let it fill up with stuff that has
> been accessed - just on the chance that it may be reused.
> 
> It hasn't even felt enough memory pressure to start swapping. When you
> say it "becomes slow", what precisely becomes slow ?

When this happens in X, the mouse drags and skips, any processes running
(like tar/gzip. ls in an empty dir takes about 10 seconds) slow down,
and it happens usually for about 10sec-2min, often for no apparent
reason.  The big decompression was just a way I can easily duplicate
it.  Oddly enough though, according to top, it caches all that memory at
once, and my free goes down to 5 megs, with the system hanging/slow to
respond, for 10sec-2min.  Even typing in the console has delay before
the characters appear, and according to top, tar and gz are both using
under 1% cpu while this happens, and about 50% of the cpu is in use by
the system (not by any processes that I can see.  kupdated goes up to
about 0.3% during this)

> 
> Also what disks do you have and how are they set up ?
> -

/dev/hdb3 on / type ext2 (rw)
/dev/hdb4 on /home type ext2 (rw)
/dev/hda1 on /dos/c type vfat (rw)
/dev/hdb1 on /dos/d type vfat (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
none on /proc type proc (rw)

and my swap is /dev/hdb2