Subject: Re: Bad response...
To: NetBSD-current Discussion List <current-users@NetBSD.ORG>
From: Frederick Bruckman <email@example.com>
Date: 08/29/2004 12:52:34
In article <m1C0o9J-0005F1C@proven.weird.com>,
firstname.lastname@example.org (Greg A. Woods) writes:
> However I agree that it's _very_ bad to be forcing paging of program
> text or data when a whole bunch of memory is "wasted" on file data,
> especially if the system's main job is to run programs with their data
> in memory, not to read and write lots of files all the time.
> What I think you want to do is make sure that the file cache _minimum_
> size is quite low, perhaps lower than it is by default (on 1.6.x it's
> 10%, and I think 5% is much more reasonable, though for your purposes 1%
> might be more than enough), so that it won't hold onto so many pages
> if/when there's demand for "higher priority" memory (they should be one
> of the first to go, but to do that you have to set the _minimum_ lower).
What you want, simply, is to raise "execmin", reserving that memory for
executable pages. I suspect 32 MB of cache or so isn't going to have many
hits on a large multi-GB disk anyhow, so you might as might as well hold
in memory that which you're certain is going to be used. The number doesn't
have to be raised much - I was able to handily serve files via NFS from
a 486 with only 16 MB, with vm.execmin at "10" or "20", whereas with the
default of "5", it took an hour just to completely boot to multi-user.