From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ming Zhang Subject: Re: RAID-5 streaming read performance Date: Thu, 14 Jul 2005 10:23:37 -0400 Message-ID: <1121351017.5544.29.camel@localhost.localdomain> References: <874qb14btr.fsf@uwo.ca> <1121220487.5552.34.camel@localhost.localdomain> <87mzorfmdx.fsf@uwo.ca> <1121257494.5504.4.camel@localhost.localdomain> <87eka2g9dp.fsf@uwo.ca> <1121259126.5504.14.camel@localhost.localdomain> <87vf3eeqe2.fsf@uwo.ca> <42D5573A.6090801@dgreaves.com> <87r7e23uo5.fsf@uwo.ca> <1121344255.5544.7.camel@localhost.localdomain> Reply-To: mingz@ele.uri.edu Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1121344255.5544.7.camel@localhost.localdomain> Sender: linux-raid-owner@vger.kernel.org To: Dan Christensen Cc: David Greaves , Linux RAID List-Id: linux-raid.ids my problem here. this only apply to sdX not mdX. pls ignore this. ming On Thu, 2005-07-14 at 08:30 -0400, Ming Zhang wrote: > > Also, is there a way to disable caching of reads? Having to clear > > the cache by reading 900M each time slows down testing. I guess > > I could reboot with mem=100M, but it'd be nice to disable/enable > > caching on the fly. Hmm, maybe I can just run something like > > memtest which locks a bunch of ram... > after you run your code, check the meminfo, the cached value might be > much lower than u expected. my feeling is that linux page cache will > discard all cache if last file handle closed. >