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From: mouth@ibm.net (John Kelly) Newsgroups: comp.unix.bsd.freebsd.misc,comp.os.linux.misc,comp.os.linux.networking Subject: Re: Network Performance Date: Thu, 26 Jun 1997 17:21:48 GMT Message-ID: <33b4937d.6825648@news-s01.ny.us.ibm.net> References: <slrn5qngmn.ie2.jlc@mass-pc.wpi.edu> <5oh9h1$fuc$1@news9.gte.net> <33AC4AC3.2C67@Houston-InterWeb.COM> <5opk40$aho@nusakan.cedar.buffalo.edu> X-Newsreader: Forte Agent 1.01/32.397 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit NNTP-Posting-Host: 129.37.195.227 Lines: 52 Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.cs.su.oz.au!inferno.mpx.com.au!news.ci.com.au!brian.telstra.net!act.news.telstra.net!vic.news.telstra.net!news.mira.net.au!news.vbc.net!vbcnet-west!bulb.garlic.com!news.scruz.net!noos.hooked.net!www.nntp.primenet.com!nntp.primenet.com!news.mathworks.com!cam-news-hub1.bbnplanet.com!cpk-news-hub1.bbnplanet.com!news.bbnplanet.com!newsm.ibm.net!ibm.net!news1.ibm.net!129.37.195.227 Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:43588 comp.os.linux.misc:182330 comp.os.linux.networking:82707 On 24 Jun 1997 19:09:52 -0400, Ajay Shekhawat wrote: >> Linux ... I haven't seem anything that really impressed me. > > Not to start any flamewars here, but we've had the opposite experience I thought I would never use FreeBSD until I stress tested Linux. With Linux, I started a big download on my PPP link from an uncrowded FTP site to produce a continuous stream of inbound packets and the modem RD light went solid red. Then I used Midnight Commander to start a big directory copy of SLAKWARE from my Slackware CD to my hard drive. After only a few seconds, the download fell over dead because TCP stopped acknowledging packets (you can tell by watching the TD light on the modem -- that's how you know whether the remote machine has stopped sending or whether your machine has stopped acknowledging). The RD light blipped occasionally as the remote site tried to resend its last unacknowledged packet, but Linux refused to acknowledge any further inbound packets until the copy from CD to disk ended. I followed all the Linux performance recommendations about using IRQtune, etc. to no avail. I have repeated this test many times, and it always produces the same result under Linux 2.0.29 or 2.0.30. These versions of Linux cannot handle heavy disk I/O and network activity at the same time. Running the same stress test on the very same machine with the very same hardware under FreeBSD 2.2.1(or later) and kernel mode PPP produces a much different result. The download is running, the modem RD light is solid red, and TD regularly blips as packets are acknowledged. Then I fire up the copy from CD to disk, and wait for the download to die ... waiting ... waiting ... waiting ... one minute goes by ... two minutes go by ... after 2 minutes 45 seconds the copy from CD to disk completes ... all the while the RD light on the modem stays solid red. FreeBSD never misses a packet! I can repeat this test any number of times with the same result -- FreeBSD never blinks. This indicates that FreeBSD has superior interrupt handling, and it convinced me to learn more about FreeBSD. I performed the same test with Linux 2.1.42, but the results are inconclusive -- it worked well one time but not the next -- and I haven't yet had time to further test Linux 2.1.X. John