Re: Page cache write performance issue

[Nathan Scott <nathans@sgi.com>]

On Wed, Oct 13, 2004 at 08:20:41PM -0700, Andrew Morton wrote:
> Nathan Scott <nathans@sgi.com> wrote:
> >  I just tried switching CONFIG_HIGHMEM off, and so running the
> >  machine with 512MB; then adjusted the test to write 256M into
> >  the page cache, again in 1K sequential chunks.  A similar mis-
> >  behaviour happens, though the numbers are slightly better (up
> >  from ~4 to ~6.5MB/sec).  Both ext2 and xfs see this.  When I
> >  drop the file size down to 128M with this kernel, I see good
> >  results again (as we'd expect).
> 
> No such problem here, with
> 
> 	dd if=/dev/zero of=x bs=1k count=128k
> 
> on a 256MB machine.  xfs and ext2.

Yup, rebooted with mem=128M and on my box, & that crawls.
Maybe its just this old hunk 'o junk, I suppose; odd that
2.6.8 was OK with this though.

> Can you exhibit this one more than one machine?

I haven't got a second ia32 box atm - setting one up soon,
will let you know how it goes.

> Silly question: what does `grep sync' /etc/fstab say over there? ;)

Same thing it said on 2.6.8. :)  Nada.

cheers.

-- 
Nathan