Date: Tue, 26 Feb 2008 22:53:29 -0800 From: "Ted Mittelstaedt" <tedm@toybox.placo.com> To: "Nikos Vassiliadis" <nvass@teledomenet.gr>, <freebsd-questions@freebsd.org> Cc: Dylan Smith <dylan@lightray.org> Subject: RE: Normal CPU usage with a PPP connection Message-ID: <BMEDLGAENEKCJFGODFOCKEGLCFAA.tedm@toybox.placo.com> In-Reply-To: <200802261148.47946.nvass@teledomenet.gr>
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> -----Original Message----- > From: owner-freebsd-questions@freebsd.org > [mailto:owner-freebsd-questions@freebsd.org]On Behalf Of Nikos > Vassiliadis > Sent: Tuesday, February 26, 2008 1:49 AM > To: freebsd-questions@freebsd.org > Cc: Dylan Smith > Subject: Re: Normal CPU usage with a PPP connection > > > On Sunday 24 February 2008 14:34:37 Dylan Smith wrote: > > Hey guys, i'm running 6.3-R with (i think) userland ppp to connect to my > > ADSL provider over PPPoE. > > I build a number of graphs(mrtg) for system stats and i am noticing that > > under heavy load on my ppp connection, that is sustained 150KB/s for an > > hour or so my cpu usage, based on my graph, hovers around 20% (haven't > > looked at it in top yet but if there isn't a simple solution/reason for > > this i will look into what sort of usage it is). > > You should check top and tcpdump, it might be a big number of small > packets causing the load. > > > The box is a home > > router/server so at any 1 time isn't doing anything else that i can see > > would account for this. I also noticed that this usage increase does not > > occur with traffic coming/going on the inward facing interface, which > > regularly has transfer speeds around 10 MB/s. > > > > I'm running a AMD X2 3800+ with 2GB ram. Is this sort of usage normal? > > Can't really tell if it's normal, but it is known that userland ppp uses > much resources. I have seen it too using 20% CPU time running on > a much slower machine(I faintly remember that it was a Pentium > Celeron at 300MHz) and a much slower(384/128?) ADSL line. > > > Is there something i can do to bring it down? > > Fortunately yes, you could use net/mpd. The CPU load then, > will probably be near zero for normal traffic, the 150KB/s you > mention. If a million of small packets arrive at your router the > load will be higher, nevertheless orders of magnitude lower > than the load caused by userland ppp. > Or, you can ignore it? You still have 80% of the CPU doing nothing.... Ted
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