Date: Wed, 05 Oct 2005 14:21:45 +0200 From: Ferdinand Goldmann <ferdinand.goldmann@jku.at> To: net@freebsd.org Subject: Re: dummynet, em driver, device polling issues :-(( Message-ID: <4343C559.5000000@jku.at> In-Reply-To: <979B163D-7078-4558-9095-DC329707A5B4@dragondata.com> References: <4341089F.7010504@jku.at> <20051003104548.GB70355@cell.sick.ru> <4341242F.9060602@jku.at> <20051003123210.GF70355@cell.sick.ru> <43426EF3.3020404@jku.at> <9CD8C672-1EF2-42FE-A61E-83DC684C893D@dragondata.com> <43429157.90606@jku.at> <4342987D.7000200@benswebs.com> <20051004161217.GB43195@obiwan.tataz.chchile.org> <1128470191.75484.TMDA@seddon.ca> <979B163D-7078-4558-9095-DC329707A5B4@dragondata.com>
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Kevin Day wrote: > In one case, we had a system acting as a router. It was a Dell PowerEdge > 2650, with two dual "server" adapters. each were on separate PCI busses. > 3 were "lan" links, and one was a "wan" link. The lan links were > receiving about 300mbps each, all going out the "wan" link at near > 900mbps at peak. We were never able to get above 944mbps, but I never > cared enough to figure out where the bottleneck was there. 944mbps is a very good value, anyway. What we see in our setup are throuput rates around 300mbps or below. When testing with tcpspray, throughput hardly exceeded 13MB/s. Are you running vlans on your interface? Our em0-card connects several sites together, which are all sitting on separate vlan interfaces for which the em0 acts as parent interface. > This was with PCI-X, and a pretty stripped config on the server side. Maybe this makes a difference, too. We only have a quite old xSeries 330 with PCI and a 1.2GHz CPU. > > Nothing fancy on polling, i think we set HZ to 10000 Ten-thousand? Or is this a typo, and did you mean thousand? This is weird. :-( Please, is there any good documentation on tuning device polling? The man page does not give any useful pointers about values to use for Gbit cards. I have already read things about people using 2000, 4000HZ ... Gaaah! I tried with 1000 and 2000 so far, without good results. It seems like everybody makes wild assumptions on what values to use for polling. >, turned on > idle_poll, and set user_frac to 10 because we had some cpu hungry tasks > that were not a high priority. I think I red somewhere about problems with idle_poll. How high is your burst_max value? Are you seeing a lot of ierrs? *sigh* :-( confusing. -- >> Ferdinand Goldmann //// | | >> EMail: Ferdinand.Goldmann@zid.uni-linz.ac.at |--00 | UNIX | >> Tel. : +43/732/2468/9398 Fax. : +43/732/2468/9397 C ^ | | >> EMail: Ferdinand.Goldmann@zid.uni-linz.ac.at \ ~/ ~~~|~~~~~~~~ >> PGP D4CF 8AA4 4B2A 7B88 65CA 5EDC 0A9B FA9A 13EA B993| |-----3
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