Re: vmscan.c heuristic adjustment for smaller systems

From: Marc Singer
Date: Sat Apr 17 2004 - 16:54:13 EST

On Sat, Apr 17, 2004 at 02:33:33PM -0700, William Lee Irwin III wrote:
> On Sat, Apr 17, 2004 at 12:38:55PM -0700, William Lee Irwin III wrote:
> >> Marc Singer reported an issue where an embedded ARM system performed
> >> poorly due to page replacement potentially prematurely replacing
> >> mapped memory where there was very little mapped pagecache in use to
> >> begin with.
> >> Marc Singer has results where this is an improvement, and hopefully can
> >> clarify as-needed. Help determining whether this policy change is an
> >> improvement for a broader variety of systems would be appreciated.
> On Sat, Apr 17, 2004 at 02:29:58PM -0700, Marc Singer wrote:
> > I have some numbers to clarify the 'improvement'.
> > Setup:
> > ARM922 CPU, 200MHz, 32MiB RAM
> > NFS mounted rootfs, tcp, hard, v3, 4K blocks
> > Test application copies 41MiB file and prints the elapsed time
> > The two scenarios differ only in the setting of /proc/sys/vm/swappiness.
> This doesn't match your first response. Anyway, this one is gets
> scrapped. I guess if swappiness solves it, then so much the better.

Huh? Where do you see a discrepency? I don't think I claimed that
the test program performance changed. The noticeable difference is in
interactivity once the page cache fills. IMHO, 30 seconds to do a
file listing on /proc is extreme.

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