From owner-freebsd-hackers@FreeBSD.ORG Sat Jun 9 09:59:33 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6D009106566B; Sat, 9 Jun 2012 09:59:33 +0000 (UTC) (envelope-from rwatson@freebsd.org) Received: from cyrus.watson.org (cyrus.watson.org [65.122.17.42]) by mx1.freebsd.org (Postfix) with ESMTP id 3DDAB8FC15; Sat, 9 Jun 2012 09:59:33 +0000 (UTC) Received: from [192.168.2.102] (host109-153-160-182.range109-153.btcentralplus.com [109.153.160.182]) by cyrus.watson.org (Postfix) with ESMTPSA id 924EF46B32; Sat, 9 Jun 2012 05:59:31 -0400 (EDT) Mime-Version: 1.0 (Apple Message framework v1257) Content-Type: text/plain; charset=us-ascii From: "Robert N. M. Watson" In-Reply-To: <86k3zglsvm.fsf@kopusha.home.net> Date: Sat, 9 Jun 2012 10:59:28 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: <43D7AF1B-9BDB-4417-AF34-E75FB203A2B2@freebsd.org> References: <86sje5kkl6.fsf@kopusha.home.net> <20120609083822.GJ85127@deviant.kiev.zoral.com.ua> <86obosluvk.fsf@kopusha.home.net> <20120609090740.GL85127@deviant.kiev.zoral.com.ua> <86k3zglsvm.fsf@kopusha.home.net> To: Mikolaj Golub X-Mailer: Apple Mail (2.1257) Cc: Konstantin Belousov , Wojciech Puchar , Alan Cox , Ivan Voras , freebsd-hackers@freebsd.org Subject: Re: SuperPages utilization survey X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 09 Jun 2012 09:59:33 -0000 On 9 Jun 2012, at 10:46, Mikolaj Golub wrote: > On Sat, 9 Jun 2012 12:07:40 +0300 Konstantin Belousov wrote: >=20 > KB> Well, if I see a report informing me that some 2M region contains = 512 super > KB> pages, how should I interpret it ? For me, it is only one = superpage (mapping) > KB> that can be created in one 2M region. >=20 > Well, if I see a report like below: >=20 > PID START END PRT RES PRES SUP REF = SHD FL TP PATH > 48568 0x800c00000 0x820c00000 rw- 131072 0 51712 2 = 0 --S df=20 >=20 > it tells me that for the region 0x800c00000-0x820c00000 (512Mb) we = have 131072 > * 4k =3D 512Mb resident and 51712 * 4k =3D 202Mb (a litle less than a = half of the > region) promoted (mapped) to superpages. >=20 > If I had number of superpages here I would need additional knowledge = (a > superpage size) to calculate how effectively superpages are used. >=20 > But actually, no much difference for me. To get a number of superpages = is it > enough just to divide the result obtained counting normal-sized pages = by > (2M/4k) factor? Remember also that superpage sizes are not necessarily 2M on all = architectures, and in principle, many different page sizes might be = simultaneously supported (e.g., on MIPS). I wonder if there's some way = to capture that notion in the output somewhere so that, if we start = supporting more granular page size control (something Alan might comment = on), tool output doesn't need to be changed. Robert