From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 26 Aug 2001 18:33:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 26 Aug 2001 18:33:43 -0400 Received: from smtp.mailbox.net.uk ([195.82.125.32]:19175 "EHLO smtp.mailbox.net.uk") by vger.kernel.org with ESMTP id ; Sun, 26 Aug 2001 18:33:30 -0400 Date: Sun, 26 Aug 2001 23:33:43 +0100 From: Russell King To: Daniel Phillips Cc: Rik van Riel , pcg@goof.com, Roger Larsson , linux-kernel@vger.kernel.org Subject: Re: [resent PATCH] Re: very slow parallel read performance Message-ID: <20010826233343.A6193@flint.arm.linux.org.uk> In-Reply-To: <20010826200133Z16190-32385+242@humbolt.nl.linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010826200133Z16190-32385+242@humbolt.nl.linux.org>; from phillips@bonn-fries.net on Sun, Aug 26, 2001 at 10:08:07PM +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 26, 2001 at 10:08:07PM +0200, Daniel Phillips wrote: > No, he's streaming mp3's: I'd like to take the time to share some extra information on the VM state of Nico's system. It consists of a log of the state of every single page in his system, which was taken after he hit the point of no progress, and consists of the following output: Zone: free 255, inactive clean 26, inactive dirty 0 min 255, low 510, high 765 c04fd000: 0 00000002 00000000 [----] -- [---] c04fe000: 1 00000002 00000000 [--s-] -- [---] c04ff000: 1 00000000 c180f0f8 [----] -- [-c-] c0500000: 1 00000002 00000000 [--s-] -- [---] c0501000: 1 00000005 00000000 [----] -- [---] c0502000: 1 00000002 00000000 [--s-] -- [---] c05af000: 1 00000005 00000000 [----] -- [---] c05b0000: 1 00000005 00000000 [----] -- [---] c05b1000: 1 00000005 00000000 [----] -- [---] c05b2000: 1 00000011 00000000 [----] -- [---] c05b3000: 1 00000005 00000000 [----] -- [---] c05b4000: 1 00000008 00000000 [----] -- [---] In order, that is: virtual page address page->count paeg->age page->mapping Then 4 flags: R - reserved S - swap cache s - slab page r - (not really a flag) ramdisk page Then 2 flags: r - referenced D - dirty Then 3 list flags: a - active list d - inactive dirty list c - inactive clean list It's a little big (380K), so I won't post it here, but I'll provide a summary of the state: Of the 8192 pages in his system, there are 4687 anonymous pages like the above, 466 slab pages, 636 reserved pages, 376 unused pages (for reserved allocation) and 2000 ramdisk pages. That leaves 27 pages, which are the 26 inactive clean pages (from the above), plus one page cache page. Feel free to use this information to formulate new strategies on improving the VM. [note that it takes around 1 minute to get 32MB-worth of information out of a serial console at 38400 baud. You don't want to do this on GB boxes]. Thanks. -- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html