Date: Sat, 24 Jun 1995 13:48:25 -0700 From: David Greenman <davidg@Root.COM> To: Network Coordinator <nc@ai.net> Cc: hackers@freebsd.org Subject: Re: FreeBSD as a router Message-ID: <199506242048.NAA00597@corbin.Root.COM> In-Reply-To: Your message of "Sat, 24 Jun 95 16:39:12 EDT." <Pine.BSF.3.91.950624162711.1447G-100000@aries.ai.net>
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>> On a fast Pentium, it is possible to route packets at a rate >70Mbits/sec >> in FreeBSD-current. ...but this is talking raw data throughput. In terms of >> packets/sec, we don't do so well...about 10000 packets/sec is about tops. This >> is less than 1/10th the capability of 100BASE-TX. >> > >[I'm not questioning your results here, just curious.] How did you get >the estimate of performance on a pentium? I tried [just to see a ball >park figure] a tcpblast on 127.0.0.1 on a moderately loaded 486/66 and >got about 1.1 Megabytes/second or 9.1 Mbits/second. I seem to have some >foggy idea that the top limit of an ISA motherboard is about 10 >megabits/second, but that sounds too much like the standard ether limit. Um, we were talking about router performance...not the ability to send data through a TCP socket to localhost. Very different things. >On a pentium, we are under the assumption that the bus and processor >aren't the limiting factor, and just BSD is slowing things down. So what >is it? I think we should assume high performance hardware. The difference in cost between a Pentium-90 w/PCI (bus mastering DMA) ethernet card and a 486/66 w/ISA ether is fairly small these days (unless of course you already have the 486/66...). The limitation is definately software at this point. That's why we do well in bytes/sec, but poorly in packets/sec. >high. On higher utilized networks, I can't imagine 10-12 ms latency on a >80 megabit stream of packets is a problem. We're not talking anywhere near that much delay. ...More like 700-800us. Again, the problem isn't latency or 'bandwidth'. The problem is packets/sec. -DG
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