Date: Tue, 20 Mar 2001 08:04:27 +0100 From: =?iso-8859-1?Q?M=E5rten_Wikstr=F6m?= <Marten.Wikstrom@framfab.se> To: "'Dennis'" <dennis@etinc.com> Cc: "'freebsd-hackers@freebsd.org'" <freebsd-hackers@freebsd.org> Subject: RE: Routing latency Message-ID: <E6D22E487D45D411931B00508BCF93E75C0331@storeg001.framfab.se>
index | next in thread | raw e-mail
[snip] > >triggers every second and steals too much cpu. So my > question is, how can I > >decrease this routing delay? > Were you loading the interface, or just passing nominal > streams? What pps > did you pass through the box? Most likely the "delays" are > only seen when > the machine is close to capacity (the slow CPU you are using > doesnt help). I sent 20000 packets/s, three UDP streams with 60, 200 and 1000 bytes sized packets respectively. I also tried just one stream with 60 bytes packets and the same behaviour occured. > Latency under load and general latency are very different. Differing > methods of handling backup conditions may have different > goals; the proper > goal is overall stability and NOT packet efficiency. It > doesnt matter how > fast a man runs if he doesnt finish the race. > The problem with LINUX is that it works to a point and then > chokes, while > freebsd works up to higher thresholds. You cant evaluate a > subsystem with > one somewhat bogus test, without looking at the system as a whole. Yep, that is exactly what my test showed when I tested the packet throughput capacity. Linux choked at 27000 pps and then the output rate _decreased_ with higher input rate, whereas the FreeBSD box started to drop packets at 19000 packets/s but the throughput did still increase up untill approximately 40000 pps. (output rate). The input rate was then 70000 pps. > If you are using the dc driver, make certain it is operating in > store-and-forward mode, the default configuration starts in a > mode that > only works on 10mb/s connections. I'm using the de driver. Alas, the NICs seems quite old. They are 21140's. I've only got one 21143. I think there is a 3COM 3c905b in the lab too. Would it be better to use the 21143 + 3com than two 21140s? /Mårten To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the messagehelp
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?E6D22E487D45D411931B00508BCF93E75C0331>