Date: Thu, 26 Oct 2000 10:50:13 -0500 (CDT) From: Joe Greco <jgreco@ns.sol.net> To: freebsd-hardware@freebsd.org Cc: peter.jeremy@alcatel.com.au, dmiller@search.sparks.net Subject: Re: Multiple PCI busses? Message-ID: <200010261550.KAA26145@aurora.sol.net> In-Reply-To: <200010261534.KAA01516@earth.execpc.com> from "jgreco@execpc.com" at Oct 26, 2000 10:34:34 AM
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> > Last February I did some experimenting using a P-133 box and could > > route just over 10,000 (small) packets/sec (CPU limited) between > > different LANs. The throughput testing gave me pretty much wire > > speed[1]. This was using a couple of Intel Pro/100+ cards connecting > > to 100baseTX half-duplex hubs. Based on this, I'd say you'd be > > looking at hundreds of thousands of packets/sec on a high-end > > processor. Your overall throughput would come down to bus bandwidth > > (PCI and RAM). I'm curious about this: since a "high-end" processor isn't really ten times faster than a P133, why do you believe that you'd be able to do hundred_s_ of thousands of packets per second? (I've done testing of this sort in the past, but don't happen to have the numbers handy) > > > Is this an area where a big cache on a > > >xeon processor would help more than extra CPU cycles? > > > > As long as routing code, device driver code and your routing tables > > fit into the cache, you should be OK. Cache is pretty much irrelevant > > That won't work, full 'net BGP tables aren't going to fit into the cache:) Why are you concerned about full 'net BGP tables? Are you really sending data to all ~90,000 advertised routes out there simultaneously? Or is it more likely that you're actively sending many packets to a few hundred? With an average routetbl entry of ~136 bytes, that's very likely to at least mostly make it into cache. A nice large cache should minimally make a very large dent in main memory thrashing. ... JG To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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