From owner-freebsd-stable  Fri May  4 10: 7:33 2001
Delivered-To: freebsd-stable@freebsd.org
Received: from earth.backplane.com (earth-nat-cw.backplane.com [208.161.114.67])
	by hub.freebsd.org (Postfix) with ESMTP id 1EC3837B423
	for <freebsd-stable@FreeBSD.ORG>; Fri,  4 May 2001 10:07:29 -0700 (PDT)
	(envelope-from dillon@earth.backplane.com)
Received: (from dillon@localhost)
	by earth.backplane.com (8.11.2/8.11.2) id f44H7Rw26684;
	Fri, 4 May 2001 10:07:27 -0700 (PDT)
	(envelope-from dillon)
Date: Fri, 4 May 2001 10:07:27 -0700 (PDT)
From: Matt Dillon <dillon@earth.backplane.com>
Message-Id: <200105041707.f44H7Rw26684@earth.backplane.com>
To: John Merryweather Cooper <jmcoopr@webmail.bmi.net>
Cc: David Petrou <dpetrou@cs.cmu.edu>, Antoine.Beaupre@ericsson.ca,
	freebsd-stable@FreeBSD.ORG
Subject: Re: Should /sys/i386/conf/GENERIC's SysV shared memory 
 settings+defaults  be re-thought?
References: <20010503221951.G47670@amant.pdl.cs.cmu.edu> <200105041614.f44GEsb25774@earth.backplane.com> <3AF2DBFD.37AA2124@webmail.bmi.net>
Sender: owner-freebsd-stable@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG


:> 
:>     In general there is no downside.  Shared memory is swap-backed
:>     (though the in-kernel control structures are not).
:> 
:>     I think it's high time that the system defaults be raised.  I'll do
:>     it later today.  You should also be able to raise the defaults
:>     using appropriate sysctl's, e.g.:
:> 
:>     sysctl -a | fgrep kern.ipc
:>     sysctl -w kern.ipc.shmmax=33554432
:> 
:>     And, of course, with kernel conf variables.
:> 
:>                                                 -Matt
:
:Excellent!  Other than larger swap usage, I haven't seen a downside to
:my settings (although I think they're a little on the large end) 
:Performance with graphics, particularly with xscreensaver seems much
:improved though.
:
:jmc

    Could you do me a favor and post your 'ipcs -a' output for the case
    of your nominally heavy X load?

    I am looking to raise the SHMMAXPGS default from 1024 to 8192,
    SHMMNI from 96 to 192, and SHMSEG from 64 to 128.  The question is
    whether I have to raise SHMMNI and SHMSEG even higher -- I'm guessing
    that your problems were mostly due to the too-low SHMMAXPGS default.

						-Matt

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