From owner-freebsd-questions  Thu May 28 17:21:48 1998
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Received: (from majordom@localhost)
          by hub.freebsd.org (8.8.8/8.8.8) id RAA02608
          for freebsd-questions-outgoing; Thu, 28 May 1998 17:21:48 -0700 (PDT)
          (envelope-from owner-freebsd-questions@FreeBSD.ORG)
Received: from implode.root.com (implode.root.com [198.145.90.17])
          by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id RAA02463
          for <questions@FreeBSD.ORG>; Thu, 28 May 1998 17:21:16 -0700 (PDT)
          (envelope-from root@implode.root.com)
Received: from implode.root.com (localhost [127.0.0.1])
	by implode.root.com (8.8.5/8.8.5) with ESMTP id RAA18059;
	Thu, 28 May 1998 17:19:50 -0700 (PDT)
Message-Id: <199805290019.RAA18059@implode.root.com>
To: "Ronald F. Guilmette" <rfg@monkeys.com>
cc: Doug White <dwhite@resnet.uoregon.edu>, questions@FreeBSD.ORG
Subject: Re: How do I find out how much memory the kernel is using now? 
In-reply-to: Your message of "Wed, 27 May 1998 15:31:02 PDT."
             <27896.896308262@monkeys.com> 
From: David Greenman <dg@root.com>
Reply-To: dg@root.com
Date: Thu, 28 May 1998 17:19:50 -0700
Sender: owner-freebsd-questions@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

>Due to some goofy partitioning left over from another project, I have a
>HUGE 1.5 GB swap partition.  Top shows that (on average) I am only using
>about 1% of that, which superficially sounds quite modest and OK, until
>I looked more closely and saw that the truth of that matter is that I'm
>constantly using about 18 MB of swap... mostly due to a single big process
>that I know is thrashing its actual working set a lot.
>
>So at last I have my answer.  I need to put at least 18 MB more main memory
>into this machine in order to get it to stop behaving like a whashing machine
>with a unbalanced load set to the `spin' cycle. :-)  I'll be doing that
>forthwith.

   FreeBSD will swap out idle pages even when you have plenty of RAM for
the process. It does this to make more room for the disk cache...and this
behavior does improve overall performance. So it isn't uncommon to have
some stuff in swap even though the system isn't paging heavily. The thing
to watch for is pageins/outs which top also displays when they occur.
A high rate of paging is bad, but a page or three every few seconds is
nothing to worry about.

-DG

David Greenman
Co-founder/Principal Architect, The FreeBSD Project

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message