Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 04 May 2001 09:42:37 -0700
From:      John Merryweather Cooper <jmcoopr@webmail.bmi.net>
To:        Matt Dillon <dillon@earth.backplane.com>
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?
Message-ID:  <3AF2DBFD.37AA2124@webmail.bmi.net>
References:  <20010503221951.G47670@amant.pdl.cs.cmu.edu> <200105041614.f44GEsb25774@earth.backplane.com>

next in thread | previous in thread | raw e-mail | index | archive | help
Matt Dillon wrote:
> 
> :..
> :> while now, on a Pentium 166Mhz with 32M but around 100-150Mb or swap.
> :>
> :> Never had problems with SHM.
> :
> :i've commented about the problems with shm and a heavy enlightenment /
> :gnome load a few weeks ago to stable, but my message was pretty much
> :ignored.  also note that this issue has been brought up in current a
> :year or so ago.
> :
> :my problems went away with:
> :
> :  options  SHMMAXPGS=8192
> :  options  SHMMNI=4096
> :  options  SHMSEG=1024
> :
> :i don't know enough about the internals to know the downside for using
> :these high values, but i'm pretty confident on today's architectures
> :...
> :
> :david
> 
>     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

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




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3AF2DBFD.37AA2124>