Return to BSD News archive
Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.cs.su.oz.au!metro!metro!munnari.OZ.AU!news.ecn.uoknor.edu!news.wildstar.net!news.ececs.uc.edu!cloudbreak.rs.itd.umich.edu!newsxfer3.itd.umich.edu!howland.erols.net!news.bbnplanet.com!cam-news-hub1.bbnplanet.com!uunet!in1.uu.net!192.207.105.50!prodigy.com!darkstar.prodigy.com!davidsen From: davidsen@tmr.com (bill davidsen) Newsgroups: comp.os.linux.networking,comp.unix.bsd.bsdi.misc,comp.unix.bsd.misc Subject: Re: Linux vs BSD Date: 5 Feb 1997 20:35:08 GMT Organization: TMR Associates, Schenectady NY Lines: 32 Message-ID: <5daqts$1f74@usenet1y.prodigy.net> References: <32DFFEAB.7704@usa.net> <5cabgm$hp0@fg70.rz.uni-karlsruhe.de> <5chl91$bsi@usenet.srv.cis.pitt.edu> <87d8uqu5vt.fsf@localhost.xs4all.nl> NNTP-Posting-Host: darkstar.prodigy.com Originator: davidsen@darkstar.prodigy.com Xref: euryale.cc.adfa.oz.au comp.os.linux.networking:67697 comp.unix.bsd.bsdi.misc:5938 comp.unix.bsd.misc:2390 In article <87d8uqu5vt.fsf@localhost.xs4all.nl>, Peter Mutsaers <plm@xs4all.nl> wrote: | Added extra overhead of a user space implementation (this will always | be less efficient than a kernel space implementation) your claim is | clearly made up. Also it contradicts my own experiments with a recent | Linux version at a completely clean ethernet (here at home). I question your definition of "less efficient." It's true that you will use a little less CPU writing in the kernel, but that's true of everything, and no one says "read the hardware clock directly from a user program for efficiency." In user or kernel space you should be able to drive the hardware to it's limits, and that's what counts. For portability I would use a stub in the kernel, but you could map the buffers and registers into user space, I guess. This is _not_ a plea to move the network code, just a technical comment on the posting. I have seen ftp report very high transfer speeds myself, I knew enough to disbelieve them. I wouldn't accuse someone of making up numbers because they don't know how to benchmark. To send a file of N bytes through a kernel with buffer space B the time is essentially the transfer time of (N-B) bytes. If ftp reports the rate as N/sec it is wrong, but the person reporting the number isn't necessarily lying. -- -bill davidsen (davidsen@tmr.com) "As a software development model, Anarchy does not scale well." -Dave Welch