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Subject: Virtual Memory system (was: Interesting IDE perf results)
To: joerg_wunsch@uriah.heep.sax.de
Date: Mon, 1 Apr 96 13:02:49 MET DST
From: Greg Lehey <lehey.pad@sni.de>
Cc: freebsd-hackers@freebsd.org
In-Reply-To: <199603280941.KAA24152@uriah.heep.sax.de>; from "J Wunsch" at Mar 28, 96 10:41 am
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>
> As Joe Greco wrote:
>
>> Yeah, I'm sending him a 386sx/16 with 3MB RAM and a 40MB hard disk.  :-)
>
> 2 MB, 2 MB!
>
> (I've once got it almost running in 2 MB, but this was prior to
> David's fix of the ``mb_map full'' problem.  Perhaps i should try
> again.)

On an allied subject, I get the impression that the current VM system
wastes a fair amount of memory.  I have a window which displays the
current vmstat statistics every 5 seconds, and I can't recall ever
having seen less than 3 MB free (this is on a 32 MB system).  BSD/386
will go down to 200 kB before starting to page furiously.

Obviously it makes some sense not to take free memory down too low,
but isn't it possible that the current tuning errs a bit too much on
the side of free memory?

Greg