Date: Tue, 31 Mar 1998 10:58:59 -0500 (EST) From: "Ron G. Minnich" <rminnich@Sarnoff.COM> To: freebsd-hackers@FreeBSD.ORG Subject: Re: Virtual Interface Architecture Message-ID: <Pine.SUN.3.91.980331103920.9500A-100000@terra> In-Reply-To: <199803311354.PAA22544@labinfo.iet.unipi.it>
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On Tue, 31 Mar 1998, Luigi Rizzo wrote: > Are you looking at 10us one-way > on a single machine, or on a cluster, going through the net (in > which case you also have the startup costs of the net interface, > with its few microsecond's inter-frame gap on ethernet...) ? The challenge number I put to the extreme linux conference was this: "from user-mode system call instruction to first bit on the wire, 10 microseconds". Why this? Well, UNET does it now, albeit in a somewhat ugly way. It would be far better to do it via TCP. > I assume you want the reliability that TCP gives you, but depending on > the underlying network you might not need to implement it in the protocol > stack. Probably you also want message boundaries to be preserved, > something that TCP does not guarantee. And if you want to send > different messages to different receivers, you would not like to pay > the price of opening/closing a connection each time. The problem is that if you do 'something other than tcp', you find in many cases that people recreate things like: sequence numbers retransmit see, e.g., the nfs-over-udp mess and the way it evolved. So, i want to skip that middle step (recreate tcp) and just go right to having a fast tcp. In fact, on the RP3, people who worked on that project told me that they added lost-packet checking in the software. This on an MP interconnect. anyway, the relation of this to -hackers is that it would be neat to see freebsd get to the challenge number soon. ron To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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