From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx107.postini.com [74.125.245.107]) by kanga.kvack.org (Postfix) with SMTP id 632256B0108 for ; Mon, 16 Apr 2012 14:34:24 -0400 (EDT) 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 Subject: Followup: [PATCH -mm] make swapin readahead skip over holes Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: riel@redhat.com Cc: linux-kernel@vger.kernel.org, linux-mm 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=3D24 and N=3D28, your patch made the workload run 4-9% percent faster. For N=3D16 and N=3D20, it was 5-10% slower. And for N=3D36 and N=3D40, 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: =09kernel compile "make -jN" with varying N =09measurements in elapsed seconds =09boot kernel: 3.4-rc2 =09Oracle Linux 6 distro with ext4 =09fresh reboot for each test run =09all tests run as root in multi-user mode Hardware: =09Dell Optiplex 790 =3D ~$500 =09Intel Core i5-2400 @ 3.10 GHz, 4coreX2thread, 6M cache =091GB RAM DDR3 1333Mhz (to force swapping) =09One 7200rpm SATA 6.0Gb/s drive with 8MB cache =0910GB swap partition -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org