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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!spool.mu.edu!howland.erols.net!cam-news-hub1.bbnplanet.com!news.mathworks.com!newsfeed.internetmci.com!news.sgi.com!sdd.hp.com!col.hp.com!news.dtc.hp.com!lf.hp.com!apollo.hp.com!news.waterloo.hp.com!hpax!cupnews2.cup.hp.com!raj From: raj@cup.hp.com (Rick Jones) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: 100BaseT tuning considerations? Date: 26 Aug 1996 18:41:08 GMT Organization: Hewlett-Packard's Network Computing Division Lines: 20 Message-ID: <4vsr44$iom@hpindda.cup.hp.com> References: <4vin1s$4um@server.cs.vt.edu> Reply-To: raj@cup.hp.com NNTP-Posting-Host: hpindio.cup.hp.com X-Newsreader: TIN [version 1.2 PL2.2] Carl Harris (ceharris@mal.com) wrote: : Has anyone experimented with tuning the kernel to get the most out : of 100BaseT? Seems like it could do better than the ~40 mbit/s I : can get with a stock kernel config. I'm experimenting with : transfers that involve no with no disk I/O on a not-so-loaded : system, equipped with a Pentium 120 and 32 megs EDO... How much CPU does it take for the system to drive 10 Mbit Ethernet to saturation? Since the MTU does not increase between 10BT and 100BT (nor 1000BT?), the host does not become any more "efficient" at sending bulk data. So, if you needed 25% of your CPU to go 10 Mbit/s, 40 Mbit/s with 100BT seems quite reasonable to expect. However, you should also look at the window sizes you are using and see if there are any TCP retransmissions. rick jones http://www.cup.hp.com/netperf/NetperfPage.html