From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 1 Feb 2001 03:56:36 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 1 Feb 2001 03:56:27 -0500 Received: from 13dyn174.delft.casema.net ([212.64.76.174]:31504 "EHLO abraracourcix.bitwizard.nl") by vger.kernel.org with ESMTP id ; Thu, 1 Feb 2001 03:56:20 -0500 Message-Id: <200102010856.JAA05537@cave.bitwizard.nl> Subject: Re: drive/block device write scheduling, buffer flushing? In-Reply-To: <20010131185120.B3287@home.ds9a.nl> from bert hubert at "Jan 31, 2001 06:51:21 pm" To: bert hubert Date: Thu, 1 Feb 2001 09:56:12 +0100 (MET) CC: Nathan Black , linux-kernel@vger.kernel.org From: R.E.Wolff@BitWizard.nl (Rogier Wolff) X-Mailer: ELM [version 2.4ME+ PL60 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org bert hubert wrote: > On Wed, Jan 31, 2001 at 11:52:25AM -0500, Nathan Black wrote: > > I was wondering if there is a way to make the kernel write to disk faster. > > I need to maintain a 10 MB /sec write rate to a 10K scsi disk in a computer, > > but it caches and doesn't start writing to disk until I hit about 700 MB. At > > that point, it pauses(presumably while the kernel is flushing some of the > > buffers) and I will have missed data that I am trying to capture. > > try opening with O_SYNC, or call fsync() every once in a while. Otherwise, > this sounds like an application for a raw device, whereby you can write > directly to the disk, with no caching in between. But you'll probably need to use "buffer" too. capture | buffer -m 128m > outputfile Otherwise the "fsync" can block you for say 1/10th of a second, causing loss of a few frames. (10MB per seconds sure sounds like video). Roger. -- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2137555 ** *-- BitWizard writes Linux device drivers for any device you may have! --* * There are old pilots, and there are bold pilots. * There are also old, bald pilots. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/