-p is irrelevant - it just allows you to load a different list of protocols. There's no difference in the code.
--set-pcap-nonblocking is not irrelevant? w/o --set-pcap-nonblocking the ntop web server would just appear to hang. With it, processing continues pretty much normally - that's why it's forced on in the ./configure process. (Did you look at the info.html page to see how your options were interpreted??) Other read herrings - if you read the back traffic, it's not the _atfork() that's the problem, that's just somewhere else FreeBSD is different. It's the conversion of the libpcap dispatch into a poll that causes high CPU usage. What's undocumented is the way that libpcap uses the bpf object, what's not up for question is that the virtualization of this causes the poll and the apparent hang in 'bpf' state. There's no cure - it's all implicit in FreeBSD's userland thread model. -----Burton > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Behalf Of Eirik Oeverby > Sent: Friday, July 02, 2004 9:19 AM > To: [EMAIL PROTECTED] > Subject: Re: [Ntop-dev] High CPU load on FreeBSD with -p option > > > Hoi, > > Burton M. Strauss III wrote: > > Lots - did you read docs/FAQ and the back traffic on this list > on this very > > topic? > > > > No you didn't... bad user - no candy and cookies for you! > > No bad user here, my concience is clean! ;) > > I HAVE browsed archives and googled all day, and I know all the stuff > you're referring to here. However, if you read my post again, you'll see > that the pcap nonblocking option has *no effect* for me. On 4.x, true, > it's necessary, but on 5.x, pthreads HAS the _atfork function, and I > tried both with and without the nonblock option (and all the other > debugging/troubleshooting options) - to no avail. > > So I'm sorry, but this seems to be a different issue... > > /Eirik > > > Q. I remember rumors about something not being right under FreeBSD with > > threads? > > A. Yes. See FreeBSD bug bin/17437 at > > http://www.FreeBSD.org/cgi/query-pr.cgi?pr=17437 > > > > Basically, due to limits in FreeBSD, there is no pthread_atfork() > > function. > > So, when ntop does it's fork() call to create http pages, it > can't fixup > > the Mutexes. It wrong and could conceivably cause problems. > > > > However - ntop ran for years without the pthread_atfork() > code, so we're > > no worse off in 3.0 under FreeBSD than in 2.2 or 2.1... > > > > There was a flurry of problems late in the 3.0 development > cycle having > > to > > do with a seeming deadlock of the ntop web server (it's actually not > > dead, > > just walking at about 0.001KPH). > > > > Thanks to Yeoman efforts by Stanley Hopcroft, Michal Meloun > and, well, > > me, > > we have a work-around. > > > > If you're running under FreeBSD, use the flag, > --set-pcap-nonblocking. > > > > For more on this, read the threads at gmane - look for "FreeBSD and > > pthreads" - > > that's probably the best summary. But there's stuff on this back at > > least to > > October 2003 - look for Stanley's problems with CPU usage. > > > > -----Burton > > > > > > > > > >>-----Original Message----- > >>From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > >>Behalf Of Eirik Oeverby > >>Sent: Friday, July 02, 2004 8:05 AM > >>To: [EMAIL PROTECTED] > >>Subject: [Ntop-dev] High CPU load on FreeBSD with -p option > >> > >> > >>Hi all, > >> > >>For some time now I have struggled with ntop on some (not all) of our > >>FreeBSD machines. In particular, a FreeBSD 5.2.1 machine is giving me > >>headaches: > >> > >>When running ntop (3.0) with the -p <protocol list file> parameter, > >>after a short while its CPU load skyrockets and stays at 100% (actually, > >>100% of one of the CPUs in the server). Removing the -p parameter > >>normalizes the situation. > >>Note that while the CPU load is high, ntop seems to be behaving as it > >>should, i.e. it collects traffic data and respons to webserver requests. > >>There's no obvious slowdown, though this is a dual opteron server so I > >>don't usually notice slowdowns anyway. > >> > >>Also note that the --set-pcap-nonblocking option makes no difference; it > >>probably has no significant effect on FreeBSD 5.x. > >> > >>On another server (FreeBSD 4.10), I have no problems with the -p > >>parameter whatsoever. > >> > >>Anyone got any clue what's up with this? > >> > >>Best regards, > >>Eirik �verby > >>Unicore AS > >>Oslo, Norway > >> > >> > >>_______________________________________________ > >>Ntop-dev mailing list > >>[EMAIL PROTECTED] > >>http://listgateway.unipi.it/mailman/listinfo/ntop-dev > > > > > > _______________________________________________ > > Ntop-dev mailing list > > [EMAIL PROTECTED] > > http://listgateway.unipi.it/mailman/listinfo/ntop-dev > > > > > > _______________________________________________ > Ntop-dev mailing list > [EMAIL PROTECTED] > http://listgateway.unipi.it/mailman/listinfo/ntop-dev _______________________________________________ Ntop-dev mailing list [EMAIL PROTECTED] http://listgateway.unipi.it/mailman/listinfo/ntop-dev
