From owner-freebsd-hardware Thu Oct 26 9: 4:56 2000 Delivered-To: freebsd-hardware@freebsd.org Received: from search.sparks.net (search.sparks.net [208.5.188.60]) by hub.freebsd.org (Postfix) with ESMTP id 8032537B4C5 for ; Thu, 26 Oct 2000 09:04:53 -0700 (PDT) Received: by search.sparks.net (Postfix, from userid 100) id 03357DC74; Thu, 26 Oct 2000 11:57:37 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by search.sparks.net (Postfix) with ESMTP id DBFC9DC73; Thu, 26 Oct 2000 11:57:37 -0400 (EDT) Date: Thu, 26 Oct 2000 11:57:37 -0400 (EDT) From: David Miller To: Joe Greco Cc: freebsd-hardware@freebsd.org, peter.jeremy@alcatel.com.au Subject: Re: Multiple PCI busses? In-Reply-To: <200010261550.KAA26145@aurora.sol.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org 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