From owner-freebsd-questions Sun Jan 2 16:11:38 2000 Delivered-To: freebsd-questions@freebsd.org Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by hub.freebsd.org (Postfix) with ESMTP id 3BD4314EBE for ; Sun, 2 Jan 2000 16:11:33 -0800 (PST) (envelope-from grog@freebie.lemis.com) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id KAA37587; Mon, 3 Jan 2000 10:41:23 +1030 (CST) Date: Mon, 3 Jan 2000 10:41:23 +1030 From: Greg Lehey To: R Joseph Wright Cc: freebsd-questions@FreeBSD.ORG Subject: Re: some performance issues Message-ID: <20000103104123.H1528@freebie.lemis.com> References: <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> <386FD085.93BFA305@nwlink.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0pre2i In-Reply-To: <386FD085.93BFA305@nwlink.com> WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sunday, 2 January 2000 at 14:26:13 -0800, R Joseph Wright wrote: > 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 The results don't look very likely. Did you run them against the block device? That doesn't do anything useful. I've just tried this on an LVD drive and got: Random read Sequential read Random write Sequential write ID K/sec /sec K/sec /sec K/sec /sec K/sec /sec da1 1650.5 103 1603.6 98 That does, in fact, look rather bad, but it's more typical for random access. > After that, it core dumped. At what point? Where's the core? > BTW, your book The Complete FreeBSD has been tremendously helpful! Thank > you 8) You're welcome. Greg -- 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