From owner-freebsd-questions Sun Jan 2 14:29:20 2000 Delivered-To: freebsd-questions@freebsd.org Received: from smtp.nwlink.com (smtp.nwlink.com [209.20.130.57]) by hub.freebsd.org (Postfix) with ESMTP id 81E8F14EAA for ; Sun, 2 Jan 2000 14:29:18 -0800 (PST) (envelope-from rjoseph@nwlink.com) Received: from nwlink.com (ip82.r2.d.bel.nwlink.com [207.202.172.82]) by smtp.nwlink.com (8.9.3/8.9.3) with ESMTP id OAA06256 for ; Sun, 2 Jan 2000 14:29:17 -0800 (PST) Message-ID: <386FD085.93BFA305@nwlink.com> Date: Sun, 02 Jan 2000 14:26:13 -0800 From: R Joseph Wright X-Mailer: Mozilla 4.51 [en] (X11; I; FreeBSD 3.4-STABLE i386) X-Accept-Language: en MIME-Version: 1.0 Cc: freebsd-questions@FreeBSD.ORG Subject: Re: some performance issues References: <386C0676.F39EC477@3-cities.com> <386C2354.ABD1ED54@nwlink.com> <386C3173.1D695393@3-cities.com> <386C543D.6E59C9DF@nwlink.com> <19991231104441.C2609@emu.sourcee.com> <386CE8AB.29A140B5@nwlink.com> <386CF9DC.B71A9887@3-cities.com> <386D3D3C.C92D02A3@nwlink.com> <386D5C88.B8257D45@3-cities.com> <386D8ABD.C2894A91@nwlink.com> <20000101160159.O1528@freebie.lemis.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Greg Lehey wrote: > iozone is not really a storage device testing program. Use rawio (in > the Ports Collection) for that: it bypasses the cache. Read carefully > the warnings which tell you that you should not use the write tests on > a file system which contains data you want to keep. > > > Kent, I tried that, only for me it worked doing "iozone 160". Here is > > my results: > > > > 11483869 bytes/second for reading > > 15155142 bytes/second for writing > > This is sequential access. You'll never get that in practice. > > > Is that really slow? It's nowhere near 33MB/second. > > 33 MB/s is the transfer rate from disk buffer to CPU. The transfer > rate off the platter is slower, and your speeds there look pretty > good. But remember that they're the ideal case. > > > I have a Maxtor 7000rpm with UDMA66 capabilities, although I'll have > > to wait for -STABLE to support that, and a new motherboard as well. > > I may recompile with the old flags just to see the difference. > > I'd be interested to see the difference, but I don't think it'll be > very much. Try both with rawio, and look at the random access > results, which are the only ones that count in practice. > > Greg I tried rawio, and got the following using flags 0xb0ffb0ff: Random Read Random Write ID K/sec /sec K/sec /sec anon 25352.3 1560 16548.4 1024 With flags set at 0x80ff80ff, I got: K/sec /sec 12992.0 806 After that, it core dumped. But I got double the speed with the new flags! I was pretty amazed. I did the test on an empty partition, so as not to disturb anything. BTW, your book The Complete FreeBSD has been tremendously helpful! Thank you 8) Joseph > -- > When replying to this message, please copy the original recipients. > For more information, see http://www.lemis.com/questions.html > Finger grog@lemis.com for PGP public key > See complete headers for address and phone numbers > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message -- Best Regards, Joseph You will do foolish things, but do them with enthusiasm. Colette. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message