Date: Thu, 26 Oct 2000 11:57:37 -0400 (EDT) From: David Miller <dmiller@search.sparks.net> To: Joe Greco <jgreco@ns.sol.net> Cc: freebsd-hardware@freebsd.org, peter.jeremy@alcatel.com.au Subject: Re: Multiple PCI busses? Message-ID: <Pine.BSF.4.21.0010261149590.32611-100000@search.sparks.net> In-Reply-To: <200010261550.KAA26145@aurora.sol.net>
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On Thu, 26 Oct 2000, Joe Greco wrote: > > > > 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? The box in question is intended for application at a NAP, feeding some packets (Maybe a few thousand/sec) out for a local site. Chance are that over any small amount of time most of the packets heading through the box will be from a small set of networks. > 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. You've probably got me here: I'd assume that the routing routines would have to do a tree search through the table to get the appropriate interface. Perhaps the significant nodes of the tree would be cached? Does freebsd support a route-cache like cisco? --- David To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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