Date: Sun, 16 Dec 2001 03:56:02 +0300 (MSK) From: "."@babolo.ru To: TD790@aol.com Cc: hackers@FreeBSD.ORG, isp@FreeBSD.ORG Subject: Re: 3Com driver problems Message-ID: <200112160056.DAA09823@aaz.links.ru> In-Reply-To: <9d.200f9846.294cf54d@aol.com> from "TD790@aol.com" at "Dec 15, 1 01:49:49 pm"
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TD790@aol.com writes: > In a message dated 12/15/2001 1:07:28 PM Eastern Standard Time, "."@babalo.ru > writes: > > > At 06:41 PM 12/14/2001, you wrote: > > >HP889@aol.com writes: > > > > Try to front end your machine with a switch...the 5 cards is most > > > likely your > > > > problem. With each device you increase your bus contention (ie worsen > > the > > > > worst case bus master scenario)...either that or get a 4 port card > that > > is > > > > more efficient than 5 individual cards. > > >I have some opposite expierence. > > >This is my biggest router: > > >0gw~(1)>uname -a > > >FreeBSD gw.pike 4.4-STABLE FreeBSD 4.4-STABLE #0: Wed Sep 19 06:29:38 MSD > > >2001 babolo@shikster.pike.ru:/tmp/babolo/usr/src/sys/gw i386 > > >0gw~(2)>ifconfig -a > > >dc0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > > >dc1: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500 > > >dc2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > > >dc3: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > > >xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > > >xl1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > > >xl2: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > > >6 used 100 M ethernet interfaces among others. > > >dc0..dc3 is one card. > > >xl0 cards are workaround for the fact that processor > > sty > > > >spent MUCH more time in interrupt state with dc driver > > >than with xl driver with the same load. > > >Yes, I try find xl x 4 card but no success > > Interrupt state and bus contention are 2 different problems...the problem > with referencing the dc driver is that there are lots of different cards with > different results. btw, the if_dc driver is one of the drivers optimized for > the alpha (note the m_devget calls)..and can use a bit of tuning. my > experience with dlink quad cards and xl is that they are similar in > performance if you account for the fact that the quad cards are going through > a pci bridge chip...and the reduction in bus contention versus using 4 cards. Mine 4 port card was bought as D-link... What is "a bit of tuning"? Yes, I played with shared and non-shared interrupts to assign non-shared to most loaded ports > One issue is that you (and alot of others) dont understand the physical I come to FreeBSD after I was a hardware developper. Hardware constraints are the things I understand well. I do not connect all high load interfaces to one router and this example has 3 relatively high load interfaces. > limits of your machine. putting 6 or more 100Mb/s ethernets on one 32bit bus > is simply asking for problems. You are dealing with a bus that BURSTs to a > bit more than a Gb and probably no more sustained throughput capability than > 500Mb/s (with 2 cards you'll get some errors at 400Mb/s and down from there > as you add cards)...so how do you expect to handle worst case DMA > requirements of 600-800Mb/s in half duplex or twice that if you run 100Mb/s > full duplex? Its just not physically possible. I have no problem with this router now. There is a home network, so no one want to pay more if quality is sufficient. The worst interface has about 1:10000 loss - it's OK. Average packet rate for last 67 days is 860 pkt/sec only, burst rate is about 5 times more for 2 min intervals. Yes, I have no direct data about real (short) bursts, but total packet loss is sufficiently low. The real restriction is IP rule complexity. -- @BABOLO http://links.ru/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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