*BSD News Article 70254


Return to BSD News archive

Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.cs.su.oz.au!metro!metro!munnari.OZ.AU!spool.mu.edu!newshub.tc.umn.edu!lynx.unm.edu!fg1.plk.af.mil!news.zynet.com!imci2!news.internetMCI.com!newsfeed.internetmci.com!uwm.edu!lll-winken.llnl.gov!sol.ctr.columbia.edu!startide.ctr.columbia.edu!wpaul
From: wpaul@ctr.columbia.edu (Bill Paul)
Newsgroups: comp.unix.bsd.freebsd.misc,comp.unix.bsd.misc,
Subject: Re: [Q] kernel help on tcp and dbx
Followup-To: comp.unix.bsd.freebsd.misc,comp.unix.bsd.misc,
Date: 5 Jun 1996 17:24:01 GMT
Organization: Columbia University Center for Telecommunications Research
Lines: 39
Message-ID: <4p4fri$b3p@sol.ctr.columbia.edu>
References: <4okasc$ra3@usenet.srv.cis.pitt.edu> <4p26qe$n21@uriah.heep.sax.de>
NNTP-Posting-Host: startide.ctr.columbia.edu
X-Newsreader: TIN [version 1.2 PL2]
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:20751 comp.unix.bsd.misc:1123

Daring to challenge the will of the almighty Leviam00se, J Wunsch
(j@uriah.heep.sax.de) had the courage to say:

: cjk@omedsrvb.omed.pitt.edu (Carl Joel Kuzmich) wrote:

: > I was getting some help from a dec rep on one of my alpha boxes and had
: > me increase "somaxcomm" using the dbx - k command.
: > 
: > My question is how can I do this from within bsd????

: It has traditionally been hard-coded into the kernel (to the value
: defined in <sys/socket.h> which was directly used by the kernel).
: FreeBSD has recently made it a tunable parameter that can also be
: tuned via the sysctl interface (and defaults to 128 now as opposed to
: 5 in traditional BSD's).

As an aside, while the sysctl is the prefered way to tune kernel
parameters on the fly, you can use the debugger to do it too.

You can set any global variable in the kernel using the following command:

# echo "set variable = 1" | gdb -q -w -k /kernel /dev/mem

This is handy if you want to tweak something that isn't mapped to
a sysctl variable.

Note that the -k flag is only available with the version of gdb that
ships with FreeBSD, as far as I know.

-Bill

--
=============================================================================
-Bill Paul            (212) 854-6020 | System Manager, Master of Unix-Fu
Work:         wpaul@ctr.columbia.edu | Center for Telecommunications Research
Home:  wpaul@skynet.ctr.columbia.edu | Columbia University, New York City
=============================================================================
 "If you're ever in trouble, go to the CTR. Ask for Bill. He will help you."
=============================================================================