*BSD News Article 73999


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From: Michael Hancock <michaelh@cet.co.jp>
Newsgroups: comp.os.linux.networking,comp.unix.bsd.netbsd.misc,comp.unix.bsd.freebsd.misc
Subject: Re: TCP latency
Date: Thu, 18 Jul 1996 02:51:06 -0700
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Alan Cox wrote:
> 
> That is one I'd like to try, and I'd be interested in the figures for both
> on the same hardware for each node you are testing against. (DONT do a dumb
> two host many connection test its got no value as the packet patterns will not
> resemble real traffic and you won't be accurately assessing issues like
> L2 cache footprint of arp table lookups. You need to model a real network
> with say 300-500 hosts off mixed subnets and on mixed traffic timers to
> generate useful stats for say WWW network performance.

*BSD servers are operating in environments like this and worse.  Talk to Matt about his 
network from hell.
 
> Well the last time I looked the VM works rather nicely now, it certainly
> seems to work rather well (unlike 1.2). It also passes the portability test
> in running on machines with 32 and 64bit architectures, as well as both
> physical and various virtual caches, while I'm dubious the FreeBSD vm subsystem
> will actually run well on a 64bit architecture - perhaps the NetBSD folk can
> answer why they use the Mach VM layer not yours ?

Because that's what 4.4BSD Lite came with.  John made radical changes to the VM and 
NetBSD probably didn't want to go thru a such a volatile phase of development.

John started with the Mach VM code and made it better.  He unified it with the buffer 
cache and has been working on various optimizations.  It was a major undertaking and 
it's stabilizing now, so more time can be spent looking at other areas of the OS.

-mike hancock