Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261588AbVBHRIS (ORCPT ); Tue, 8 Feb 2005 12:08:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261577AbVBHRGX (ORCPT ); Tue, 8 Feb 2005 12:06:23 -0500 Received: from rproxy.gmail.com ([64.233.170.206]:1516 "EHLO rproxy.gmail.com") by vger.kernel.org with ESMTP id S261582AbVBHRGO (ORCPT ); Tue, 8 Feb 2005 12:06:14 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type:content-transfer-encoding; b=hF4bnrxMTQpCE4uXx2nIkwv0lDnMEMb8idsUeD/hkHoCOHLBYU1QH43s12jxYSX3ijjOjfRr9IOf3EMMfehcMi+MDdXv7MaCXALLeTukiaOVbeVNCtouLyErCiiUfXcODViQarPjtYsja6CBS9NkW4FiZxKb/y2ZfxZ2ST1NOo4= Message-ID: Date: Tue, 8 Feb 2005 12:06:14 -0500 From: jon ross Reply-To: jon ross To: linux-kernel@vger.kernel.org Subject: VM disk cache behavior. 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 Content-Length: 981 Lines: 24 I have an app with a small fixed memory footprint that does a lot of random reads from a large file. I thought if I added more memory to the machine the VM would do more caching of the disk, but added memory does not seem to make any difference. I played with some of the params in /proc/sys/vm and none of them seem to have any effect. I tired both a 2.4.20 & 2.6.10 kernels with no difference. The machine is a Dell 2560. I tired memory configs of 512M, 1G, 4G and the average read-times do not change. Do I need to set/compile anything to allow the VM to use the memory? If is was a way to tell how much memory the VM is using for a drive cache I could at least tell if my kernel is miss-configured or my app sucks. Thanks, -Jon - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/