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From: Renaud Bruyeron <bruyeron@cs.ucla.edu>
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: kernel traces
Date: 18 Jun 1997 19:50:19 GMT
Organization: UCLA Computer Science Dept.
Lines: 14
Message-ID: <5o9e5r$1ar@delphi.cs.ucla.edu>
NNTP-Posting-Host: cheetah.cs.ucla.edu
X-Newsreader: TIN [UNIX 1.3 unoff BETA release 970120]
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:43142
I am working on TCP, and I need to plot some state variables from the TCP code on FreeBSD 2.1.6. Those variables are not available through netstat, therefore I try to 'print' these variables, since I was told printf defaults to /var/log/message within the kernel.
Even though I don't like the idea to use printf within this kind of code, I tried to, but was enable to find the result of the output anywhere:
if( (tp->t_inpcb->inp_socket->so_options & SO_DEBUG) )
printf(";TCP_VARS: cwnd=%d",tp->snd_cwnd);
I inserted this piece of code at some intereting points in tcp_input.c, and I tried to enable SO_DEBUG with a setsockopt() call, but it does not work.
Is there any kernel guru out there who could help me ? Is printf the normal way to go for this purpose (what about klog and log ?)
Thanks for your help,
- Renaud