[prev in list] [next in list] [prev in thread] [next in thread] 

List:       ntop
Subject:    RE: [Ntop] --pcap_setnonblock on by default?  Does cause
From:       "Gary Gatten" <Ggatten () waddell ! com>
Date:       2006-03-16 19:23:05
Message-ID: s41966c6.007 () gwia ! waddell ! com
[Download RAW message or body]

Thanks for the prompt reply.

I've worked with various *nix systems over the years - back to Xenix in
early 90s.  However, I am not an "admin" level by any means - at least
not a good one -  so it may take me a little time for this.

Thanks again!

Gary


>>> Burton@ntopSupport.com 3/16/2006 11:53:26 AM >>>
Probably because we haven't created a configureextras file for 6.

Copy the 5 file and try it.  If it works as expected, let us know and
we'll
add your file into the cvs.

Also, don't use ntop.sh - it's a bad idea (read the comments in it) -
do the
install and run ntop for real.

-----Burton 

-----Original Message-----
From: ntop-bounces@unipi.it [mailto:ntop-bounces@unipi.it] On Behalf Of
Gary
Gatten
Sent: Thursday, March 16, 2006 10:21 AM
To: ntop@Unipi.IT 
Subject: [Ntop] --pcap_setnonblock on by default? Does cause problems.

I have nTop 3.2 on FreeBSD 6.0.  The  --pcap_setnonblock option was
enabled
by default in the ntop.sh script.  The man page says it will cause high
cpu
load, but "it does not actually  interfere  with  other work". 
However, it
was causing problems for the netflow plugin.  The RECV queue for the
netflow
UDP port was always around 40K and I was dropping a LOT of netflow
packets.
After restarting without this option enabled, everything looks to be
working
much better.

I guess the main question I have is, if "THIS OPTION IS OFFICIALLY
UNSUPPORTED and used at your own risk", then why is it enabled by
default?

Thanks!

Gary

 --pcap_setnonblock
        On some platforms, the ntop web server will hang or appear to
hang
(it
        actually  just  responds incredibly slowly to the first request
from
a
        browser session), while the rest of ntop runs just fine. This
is
known
        to be an issue under FreeBSD 4.x.

        This  option  sets the non-blocking option (assuming it's
available
in
        the version of libpcap that is installed).

        While this works around the problem  (by  turing  an  interupt
driven
        process into a poll), it also MAY signifcantly increases the
cpu
usage
        of ntop.  Although it does not actually  interfere  with 
other
work,
        seeing  ntop use 80-90% or more of the cpu is not uncommon -
don't
say
        we didn't warn you.

        THIS OPTION IS OFFICIALLY UNSUPPORTED and used at your own
risk.
Read
        the docs/FAQ write-up.



_______________________________________________
Ntop mailing list
Ntop@unipi.it 
http://listgateway.unipi.it/mailman/listinfo/ntop 

_______________________________________________
Ntop mailing list
Ntop@unipi.it 
http://listgateway.unipi.it/mailman/listinfo/ntop


_______________________________________________
Ntop mailing list
Ntop@unipi.it
http://listgateway.unipi.it/mailman/listinfo/ntop
[prev in list] [next in list] [prev in thread] [next in thread]