From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964863AbWAIQ3W (ORCPT ); Mon, 9 Jan 2006 11:29:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964866AbWAIQ3W (ORCPT ); Mon, 9 Jan 2006 11:29:22 -0500 Received: from ns.firmix.at ([62.141.48.66]:58592 "EHLO ns.firmix.at") by vger.kernel.org with ESMTP id S964863AbWAIQ3V (ORCPT ); Mon, 9 Jan 2006 11:29:21 -0500 Subject: Re: Why the DOS has many ntfs read and write driver,but the linux can't for a long time From: Bernd Petrovitsch To: Lee Revell Cc: Oliver Neukum , Robert Hancock , linux-kernel In-Reply-To: <1136823598.9957.43.camel@mindpipe> References: <5t06S-7nB-15@gated-at.bofh.it> <200601091702.48955.oliver@neukum.org> <1136822646.9957.35.camel@mindpipe> <200601091714.27303.oliver@neukum.org> <1136823598.9957.43.camel@mindpipe> Content-Type: text/plain Organization: Firmix Software GmbH Date: Mon, 09 Jan 2006 17:29:09 +0100 Message-Id: <1136824149.5785.75.camel@tara.firmix.at> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2006-01-09 at 11:19 -0500, Lee Revell wrote: > On Mon, 2006-01-09 at 17:14 +0100, Oliver Neukum wrote: > > Am Montag, 9. Januar 2006 17:04 schrieb Lee Revell: > > > On Mon, 2006-01-09 at 17:02 +0100, Oliver Neukum wrote: > > > > Am Montag, 9. Januar 2006 16:15 schrieb Lee Revell: > > > > > On Mon, 2006-01-09 at 15:28 +0100, Oliver Neukum wrote: > > > > > > Am Montag, 9. Januar 2006 15:18 schrieb Robert Hancock: > > > > > > > Yaroslav Rastrigin wrote: > > > > > > > > Well, I could find more or less reasonable explanation of this behaviour - different VM policies of two OSes and > > > > > > > > strangely strong and persistent belief "Free RAM is a wasted RAM" among kernel devs. Free RAM is not a wasted RAM, its a memory waiting to be used ! > > > > > > > > Whenever it is needed by apps I'm launching or working with. > > > > > > > > > > > > > > There is no different VM policy here, Windows behaves quite similarly. > > > > > > > It does not leave memory around unused, it uses it for disk cache. > > > > > > > > > > > > That doesn't mean that the rate of eviction is the same. > > > > > > Is it possible that read-ahead is not aggressive enough? > > > > > > > > > > Enough for what? What is the exact problem you are trying to solve? > > > > > > > > Quicker application startup. > > > > > > Why do you look to the kernel first? The obvious explanation is that > > > Linux desktop apps are more bloated than their Windows counterparts. > > > > It is the most efficient place. An improvement to the kernel will improve > > all starting times. > > I think you'll get at most a 10% or 20% speedup by improving the kernel, > while some of these apps (think Nautilus vs Windows Explorer) will need > to be 1000% faster to seem reasonable to a Windows user. That's easy: Just start nautilus, OOorg, Firefox, a java-vm and GNOME/KDE infrastructure at login time in the background (*eg* and mlockall() the more important ones so that the are surely in RAM) and "starting the app" is only a small program connecting to the respective process to get a fork() there (e.g. like the "-remote" parameter in the Mozilla family). Bernd -- Firmix Software GmbH http://www.firmix.at/ mobil: +43 664 4416156 fax: +43 1 7890849-55 Embedded Linux Development and Services