Path: utzoo!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!pacbell.com!att!emory!wuarchive!udel!brahms.udel.edu!gdtltr From: gdtltr@brahms.udel.edu (root@research.bdi.com (Systems Research Supervisor)) Newsgroups: comp.os.mach Subject: Re: Mach RPC Throughput... Message-ID: <19748@brahms.udel.edu> Date: 18 Mar 91 19:18:02 GMT References: <9332@star.cs.vu.nl> Distribution: comp Organization: Brain Dead Innovations, Inc. (BDI) Lines: 38 In article bob@MorningStar.Com (Bob Sutterfield) writes: =>In article <9332@star.cs.vu.nl> ast@cs.vu.nl (Andy Tanenbaum) writes: => The protocol used [by Amoeba] on the Ethernet ... is not IP ... => The loss of performance when going through the TCP/IP server is not => so important because usually the TCP connections go over a => narrow-band wide-area link anyway, so there is no way to get => high-performance no matter what. In essence, we have chosen to => optimize the local case, and accepted worse performance when one => specifically wishes to speak TCP/IP. => =>What about when the non-"local" case involves RPC with a machine on a =>different Ethernet in the next room, accessible via a high-bandwidth =>IP router? IP is useful in environments other than wide area =>networks. Local distributed computing environments might involve =>multiple networks connected by routers, rather than bridges or =>repeaters, and it seems that you're designing in a penalty for Amoeba =>users whose clusters grow too big for one Ethernet. I don't want to speak for Dr. Tanenbaum, but I like to pop in every once in a while and pretend that I know what I am talking about. :-) I believe that Amoeba 4.0 deals with the multiple LAN case with a Fast Local Internet Protocol (FLIP). This adds a hint to a capability to determine which subnet the service is on. This still wouldn't handle IP-specific hardware, but it would handle more general high-bandwidth gateways. Not all of us want to be slaves to existing protocols, especially if there is greater performance to be gained through newer ones. Gary Duzan Time Lord Third Regeneration -- gdtltr@brahms.udel.edu _o_ ---------------------- _o_ [|o o|] Two CPU's are better than one; N CPU's would be real nice. [|o o|] |_o_| Disclaimer: I AM Brain Dead Innovations, Inc. |_o_|