Date: Mon, 05 Oct 2009 10:28:38 -0700 From: Julian Elischer <julian@elischer.org> To: rihad <rihad@mail.ru> Cc: freebsd-net@freebsd.org, Luigi Rizzo <rizzo@iet.unipi.it> Subject: Re: dummynet dropping too many packets Message-ID: <4ACA2CC6.70201@elischer.org> In-Reply-To: <4AC9EFDF.4080302@mail.ru> References: <20091005061025.GB55845@onelab2.iet.unipi.it> <4AC9B400.9020400@mail.ru> <20091005090102.GA70430@svzserv.kemerovo.su> <4AC9BC5A.50902@mail.ru> <20091005095600.GA73335@svzserv.kemerovo.su> <4AC9CFF7.3090208@mail.ru> <20091005110726.GA62598@onelab2.iet.unipi.it> <4AC9D87E.7000005@mail.ru> <20091005120418.GA63131@onelab2.iet.unipi.it> <4AC9E29B.6080908@mail.ru> <20091005123230.GA64167@onelab2.iet.unipi.it> <4AC9EFDF.4080302@mail.ru>
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rihad wrote: > Luigi Rizzo wrote: >> On Mon, Oct 05, 2009 at 05:12:11PM +0500, rihad wrote: >>> Luigi Rizzo wrote: >>>> On Mon, Oct 05, 2009 at 04:29:02PM +0500, rihad wrote: >>>>> Luigi Rizzo wrote: >>>> ... >>>>>> you keep omitting the important info i.e. whether individual >>>>>> pipes have drops, significant queue lenghts and so on. >>>>>> >>>>> Sorry. Almost everyone has 0 in the last Drp column, but some have >>>>> above zero. I'm not just sure how this can be helpful to anyone. >>>> because you were complaining about 'dummynet causing drops and >>>> waste of bandwidth'. >>>> Now, drops could be due to either >>>> 1) some saturation in the dummynet machine (memory shortage, cpu >>>> shortage, etc.) which cause unwanted drops; >>>> >>> I too think the box is hitting some other global limit and dropping >>> packets. If not, then how come that between 4a.m. and 10a.m. when the >>> traffic load is at 250-330 mbit/s there isn't a single drop? >> >> there may be different reasons, e.g. the big offenders were >> idle when you saw no drops. You still do not have enough >> information on which packets are dropped and where, >> so you cannot prove your assumptions. >> >> Also, below: >> 1. increasing the queue size won't help at all. Those >> who overflow a queue of 1000 slots will also overflow >> a queue of 10k slots. >> > >> 2. your test with 'ipfw allow ip from any to any' does not >> prove that the interface queue is not saturating, because >> you also remove the burstiness that dummynet introduces, >> and so the queue is driven differently. >> > > There's one thing I noticed: > net.inet.ip.dummynet.io_pkt_drop doesn't grow! But still around 400 > packets dropped per second. > net.inet.ip.dummynet.tick_lost is always zero > net.inet.ip.dummynet.tick_diff: grows at about 50 per second. > net.inet.ip.dummynet.tick_adjustment: grows at about 5 per second. > > How do I investigate and fix this burstiness issue? higher Hz rate? > > > $ netstat -i > Name Mtu Network Address Ipkts Ierrs Opkts > Oerrs Coll > bce0 1500 <Link#1> 00:1d:09:xx:xx:xx 24777049059 0 75426020 > 0 0 > bce0 1500 xx.xx.xx.xx/xx my.hostname 159293969 - 75282225 > - - > bce1 1500 <Link#2> 00:1d:09:xx:xx:xx 724725 0 24514919344 > 0 0 > bce1 1500 192.168.94.0 local.hostname 656243 - 83024869 - - > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org"
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