From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269392AbUIIJ65 (ORCPT ); Thu, 9 Sep 2004 05:58:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269398AbUIIJ65 (ORCPT ); Thu, 9 Sep 2004 05:58:57 -0400 Received: from mf2.realtek.com.tw ([220.128.56.22]:36105 "EHLO mf2.realtek.com.tw") by vger.kernel.org with ESMTP id S269392AbUIIJ6y (ORCPT ); Thu, 9 Sep 2004 05:58:54 -0400 Message-ID: <00cf01c49653$9ad48f10$8b1a13ac@realtek.com.tw> From: "colin" To: "Paulo Marques" Cc: References: <009901c4964a$be2468e0$8b1a13ac@realtek.com.tw> <4140200B.9060408@grupopie.com> Subject: =?iso-8859-1?Q?Re:_=A1@=5B*=A9U=A7=A3=B6l=A5=F3*=5D_Re:_What_File_Syste?= =?iso-8859-1?Q?m_supports_Application_XIP?= Date: Thu, 9 Sep 2004 17:58:44 +0800 MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-MIMETrack: Itemize by SMTP Server on msx/Realtek(Release 6.0.2CF1|June 9, 2003) at 2004/09/09 =?Big5?B?pFWkyCAwNTo1OTo0OA==?=, Serialize by Router on msx/Realtek(Release 6.0.2CF1|June 9, 2003) at 2004/09/09 =?Big5?B?pFWkyCAwNTo1OTo0OQ==?=, Serialize complete at 2004/09/09 =?Big5?B?pFWkyCAwNTo1OTo0OQ==?= Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="iso-8859-1" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Paulo, Cramfs seems to support it now. At the beginning, I also think it's impossible to support Application XIP in Cramfs. http://www.denx.de/twiki/publish/DULG/ConfigureLinuxForXIP.html Regards, Colin ----- Original Message ----- From: "Paulo Marques" To: "colin" Cc: Sent: Thursday, September 09, 2004 5:19 PM Subject: ¡@[*©U§£¶l¥ó*] Re: What File System supports Application XIP > colin wrote: > > > > Hi there, > > We are developing embedded Linux system. Performance is our consideration. > > We hope some applications can run as fast as possible, > > and are think if they can be put in a filesystem image, which resides in > > RAM, and run in XIP (eXecute In Place) manners. > > I know that Cramfs has supported Application XIP. Is there any other FS that > > also supports it? Ramdisk? Ramfs? Romfs? > > Obvisously cramfs can not support XIP, because the "in-place" image > is compressed (unless you have a processor that can execute compressed > code :) > > AFAIK only tmpfs supports XIP because it works on a higher level > without using block devices underneath. Ramdisks are simply RAM > block devices that behave like any other block device. > > You can have a compressed image in flash (for instance), decompress > everything into a tmpfs and execute from there. > > I'm not sure, however, that this will be such a performance gain. > > If you use cramfs (for instance) then the kernel will uncompress > and run only the pages that are needed, and they will be cached in > page cache so that they will be available again when needed. This > way you only waste the RAM you actually need, and can still drop > old pages if the application needs more RAM. > > Just my two cents, > > -- > Paulo Marques - www.grupopie.com > > To err is human, but to really foul things up requires a computer. > Farmers' Almanac, 1978 >