From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx165.postini.com [74.125.245.165]) by kanga.kvack.org (Postfix) with SMTP id 4A4F16B0007 for ; Mon, 4 Feb 2013 10:08:05 -0500 (EST) Received: from /spool/local by e9.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 4 Feb 2013 10:08:03 -0500 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id 4CC4E6E805E for ; Mon, 4 Feb 2013 10:07:58 -0500 (EST) Received: from d01av03.pok.ibm.com (d01av03.pok.ibm.com [9.56.224.217]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r14F7x4v301932 for ; Mon, 4 Feb 2013 10:07:59 -0500 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r14F7wL5025250 for ; Mon, 4 Feb 2013 13:07:59 -0200 Message-ID: <510FCECC.6020703@linux.vnet.ibm.com> Date: Mon, 04 Feb 2013 09:07:56 -0600 From: Seth Jennings MIME-Version: 1.0 Subject: Re: [PATCHv4 0/7] zswap: compressed swap caching References: <1359495627-30285-1-git-send-email-sjenning@linux.vnet.ibm.com> <1359682784.3574.2.camel@kernel> <510BDB8F.5000104@linux.vnet.ibm.com> <1359939818.9366.1.camel@kernel.cn.ibm.com> In-Reply-To: <1359939818.9366.1.camel@kernel.cn.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Simon Jeons Cc: Andrew Morton , Greg Kroah-Hartman , Nitin Gupta , Minchan Kim , Konrad Rzeszutek Wilk , Dan Magenheimer , Robert Jennings , Jenifer Hopper , Mel Gorman , Johannes Weiner , Rik van Riel , Larry Woodman , Benjamin Herrenschmidt , Dave Hansen , linux-mm@kvack.org, linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org On 02/03/2013 07:03 PM, Simon Jeons wrote: > On Fri, 2013-02-01 at 09:13 -0600, Seth Jennings wrote: >> On 01/31/2013 07:39 PM, Simon Jeons wrote: >>> Hi Seth, >>> On Tue, 2013-01-29 at 15:40 -0600, Seth Jennings wrote: >> >>>> Performance, Kernel Building: >>>> >>>> Setup >>>> ======== >>>> Gentoo w/ kernel v3.7-rc7 >>>> Quad-core i5-2500 @ 3.3GHz >>>> 512MB DDR3 1600MHz (limited with mem=512m on boot) >>>> Filesystem and swap on 80GB HDD (about 58MB/s with hdparm -t) >>>> majflt are major page faults reported by the time command >>>> pswpin/out is the delta of pswpin/out from /proc/vmstat before and after >>>> then make -jN >>>> >>>> Summary >>>> ======== >>>> * Zswap reduces I/O and improves performance at all swap pressure levels. >>>> >>>> * Under heavy swaping at 24 threads, zswap reduced I/O by 76%, saving >>>> over 1.5GB of I/O, and cut runtime in half. >>> >>> How to get your benchmark? >> >> It's just kernel building. So "make" :) >> >> I intentionally choose this workload so people wouldn't have to jump >> through hoops to replicate the results. > > Since there already have zram which can handle anonymous pages > compression, why need zswap? What's the difference of design between > zram and zswap? zram is implemented is a virtual block device. It interfaces with the block device layer, not the swap code. In fact, zram can be used as a generic compressed RAM disk, not only for compressed swap. One can think of it as a RAM disk + compression. So zram is the actual swap device while zswap is a caching layer above the swap device. zswap is not the swap device itself like zram. Hope this clears up the difference :) Seth -- 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/ . Don't email: email@kvack.org