From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ocean.emcraft.com (ocean.emcraft.com [213.221.7.182]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTP id 22F23DDE11 for ; Tue, 23 Oct 2007 02:15:14 +1000 (EST) From: Yuri Tikhonov To: Kumar Gala Subject: Re: [PATCH] ppc44x: support for 256K PAGE_SIZE Date: Mon, 22 Oct 2007 20:12:20 +0400 References: <200710181108.19413.yur@emcraft.com> <18199.60025.563689.10810@cargo.ozlabs.ibm.com> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200710222012.20316.yur@emcraft.com> Cc: linuxppc-dev@ozlabs.org, Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Friday 19 October 2007 17:24, Kumar Gala wrote: > > On Oct 18, 2007, at 6:21 PM, Paul Mackerras wrote: > > > Yuri Tikhonov writes: > > > >> The following patch adds support for 256KB PAGE_SIZE on ppc44x- > >> based boards. > >> The applications to be run on the kernel with 256KB PAGE_SIZE have > >> to be > >> built using the modified version of binutils, where the MAXPAGESIZE > >> definition is set to 0x40000 (as opposite to standard 0x10000). > > > > Have you measured the performance using a 64kB page size? If so, how > > does it compare with the 256kB page size? > > I was wondering about this as well? Isn't this technically in > violation of the ABI? No it isn't the violation. As stated in "System V ABI. PowerPC processor supplement" (on which the "Linux Standard Base Core Specification for PPC32" is based): " ... Virtual addresses and file offsets for the PowerPC processor family segments are congruent modulo 64 Kbytes (0x10000) or larger powers of 2...". So, 256 Kbytes is just a larger case. -- Yuri Tikhonov, Senior Software Engineer Emcraft Systems, www.emcraft.com