From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751188AbWJ1R2c (ORCPT ); Sat, 28 Oct 2006 13:28:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751190AbWJ1R2c (ORCPT ); Sat, 28 Oct 2006 13:28:32 -0400 Received: from [82.147.215.28] ([82.147.215.28]:39808 "EHLO raad.intranet") by vger.kernel.org with ESMTP id S1751177AbWJ1R2c (ORCPT ); Sat, 28 Oct 2006 13:28:32 -0400 From: Al Boldi To: linux-kernel@vger.kernel.org Subject: [RFC] kswapd: Kernel Swapper performance Date: Sat, 28 Oct 2006 20:31:17 +0300 User-Agent: KMail/1.5 MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Message-Id: <200610282031.17451.a1426z@gawab.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org One thing that has improved in 2.6, wrt 2.4, is swapper performance. And the difference isn't small either: ~5 fold increase in swapin performance. But swapin performance still lags swapout performance by 50%, which is a bit odd, considering swapin to be a read from disk, usually faster, and swapout to be a write to disk, usually slower. Now, this slowdown could be explained by additional seek action, caused by different apps paging-in at different times with different locations on swap. Yet, even a single app paging-out consecutive pages, and paging-in the same pages in one go, exhibits this upside-down swapout/swapin performance ratio. Improving this ratio could possibly yield a dramatic improvement in system performance under memory load (think tmpfs/swsusp/...). Thanks! -- Al