From owner-freebsd-hackers@FreeBSD.ORG Fri Sep 20 15:20:37 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 10CBBEED; Fri, 20 Sep 2013 15:20:37 +0000 (UTC) (envelope-from S.Kuzminsky@F5.com) Received: from mail.f5.com (mail.f5.com [208.85.209.139]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id D78AB2DF1; Fri, 20 Sep 2013 15:20:36 +0000 (UTC) X-IronPort-AV: E=Sophos;i="4.90,945,1371081600"; d="scan'208";a="82341759" Received: from unknown (HELO exchmail.f5net.com) ([192.168.10.235]) by seamgw02.olympus.f5net.com with ESMTP; 20 Sep 2013 15:20:36 +0000 Received: from SEAEMBX01.olympus.F5Net.com ([fe80::3440:4256:38f6:d3a0]) by SEAECAS04.olympus.F5Net.com ([::1]) with mapi id 14.03.0158.001; Fri, 20 Sep 2013 08:20:35 -0700 From: Sebastian Kuzminsky To: Patrick Dung Subject: Re: About Transparent Superpages and Non-transparent superapges Thread-Topic: About Transparent Superpages and Non-transparent superapges Thread-Index: AQHOtIlQ/xFJtaAUVEqnjcRRWECf45nN+7CAgAB+KYCAALxWAA== Date: Fri, 20 Sep 2013 15:20:35 +0000 Message-ID: References: <1379520488.49964.YahooMailNeo@web193502.mail.sg3.yahoo.com> <22E7E628-E997-4B64-B229-92E425D85084@f5.com> <1379649991.82562.YahooMailNeo@web193502.mail.sg3.yahoo.com> In-Reply-To: <1379649991.82562.YahooMailNeo@web193502.mail.sg3.yahoo.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [192.168.16.236] Content-Type: text/plain; charset="iso-8859-1" Content-ID: <1530B9B002D7CB42ADE9966BB3FBEC5E@F5.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: Sebastian Kuzminsky , "freebsd-hackers@freebsd.org" , "ivoras@freebsd.org" X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Sep 2013 15:20:37 -0000 On Sep 19, 2013, at 22:06 , Patrick Dung wrote: > >We at Line Rate (now F5) are developing support for 1 Gig superpages on = amd64. We're basing our work on 9.1.0 for now. > > > >An early preview is available here: > > > >https://github.com/Seb-LineRate/freebsd/tree/freebsd-9.1.0-1gig-pages-NO= T-READY-2 >=20 > That is cool. >=20 > What type of applications can take advantage of the 1Gb page size? > And is it transparent? Or applications need to be modified? It's transparent for the kernel: all of UMA and kmem_malloc()/kmem_free() i= s backed by 1 gig superpages. It's not transparent for userspace: applications need to pass a new flag to= mmap() to get 1 gig pages. This is useful in applications with high memory pressure, where memory band= width and TLB misses are a limiting factor. --=20 Sebastian Kuzminsky