Date: Thu, 27 Jan 2005 16:06:41 -0800 (PST) From: Arne "Wörner" <arne_woerner@yahoo.com> To: freebsd-fs@FreeBSD.ORG Subject: Re: ufs+softupdates / consistency Message-ID: <20050128000641.11484.qmail@web41204.mail.yahoo.com> In-Reply-To: <20050127040418.26913.qmail@web41205.mail.yahoo.com>
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I would like to add, that I just tried my little performance test with KNOPPIX and fsync/openO_SYNC in a little C program. The results were even better (just about 3 seconds for 1000 64k blocks). With dd and the sync call it was about 6 seconds (btw.: Linux's sync waits until the harddisc acknowledged the write order requests). Since Linux's time command said, that the process was waiting for 90% of its alive-time, I believe, that the kernel was idle, too, because 1. sending the write order request is done quite quickly (I think), and 2. most of the time hard disc is busy with re-educating the magnetic layer of its discs without talking to the kernel, so that I do not fully understand the argument, that we should write just little chunks of data to the disc (is it because concurrent read/write requests (e. g.: a user process, that wants to read something, while the kernel syncs 64MB as soon as possible) might be delayed?). I would be glad, if somebody could tell me, if there is any work in progress or completed, that allows my old SEAGATE disc to perform as good as Linux allows it to perform. If not, I would like to fix the problem. -Arne Wörner __________________________________ Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! http://my.yahoo.com
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