From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755256Ab2DPSe2 (ORCPT ); Mon, 16 Apr 2012 14:34:28 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:31230 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752699Ab2DPSe0 convert rfc822-to-8bit (ORCPT ); Mon, 16 Apr 2012 14:34:26 -0400 MIME-Version: 1.0 Message-ID: <7297ae3b-f3e1-480b-838f-69b0e09a733d@default> Date: Mon, 16 Apr 2012 11:34:12 -0700 (PDT) From: Dan Magenheimer To: riel@redhat.com Cc: linux-kernel@vger.kernel.org, linux-mm Subject: Followup: [PATCH -mm] make swapin readahead skip over holes X-Priority: 3 X-Mailer: Oracle Beehive Extensions for Outlook 2.0.1.6 (510070) [OL 12.0.6607.1000 (x86)] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT X-Source-IP: ucsinet22.oracle.com [156.151.31.94] X-CT-RefId: str=0001.0A090202.4F8C662F.005C,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Rik -- I saw this patch in 3.4-rc1 (because it caused a minor merge conflict with frontswap) and wondered about its impact. Since I had a server still set up from running benchmarks before LSFMM, I ran my kernel compile -jN workload (with N varying from 4 to 40) on 1GB of RAM, on 3.4-rc2 both with and without this patch. For values of N=24 and N=28, your patch made the workload run 4-9% percent faster. For N=16 and N=20, it was 5-10% slower. And for N=36 and N=40, it was 30%-40% slower! Is this expected? Since the swap "disk" is a partition on the one active drive, maybe the advantage is lost due to contention? Thanks, Dan commit removed 67f96aa252e606cdf6c3cf1032952ec207ec0cf0 Workload: kernel compile "make -jN" with varying N measurements in elapsed seconds boot kernel: 3.4-rc2 Oracle Linux 6 distro with ext4 fresh reboot for each test run all tests run as root in multi-user mode Hardware: Dell Optiplex 790 = ~$500 Intel Core i5-2400 @ 3.10 GHz, 4coreX2thread, 6M cache 1GB RAM DDR3 1333Mhz (to force swapping) One 7200rpm SATA 6.0Gb/s drive with 8MB cache 10GB swap partition