From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e4.ny.us.ibm.com (e4.ny.us.ibm.com [32.97.182.144]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e4.ny.us.ibm.com", Issuer "Equifax" (verified OK)) by ozlabs.org (Postfix) with ESMTP id F3EBDDDDF7 for ; Sat, 15 Sep 2007 11:22:23 +1000 (EST) Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e4.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id l8F1MKjF002385 for ; Fri, 14 Sep 2007 21:22:20 -0400 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 v8.5) with ESMTP id l8F1MK9b616826 for ; Fri, 14 Sep 2007 21:22:20 -0400 Received: from d01av03.pok.ibm.com (loopback [127.0.0.1]) by d01av03.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l8F1MKMr026511 for ; Fri, 14 Sep 2007 21:22:20 -0400 Subject: Re: [PATCH] add Kconfig option for optimizing for cell From: Josh Boyer To: Arnd Bergmann In-Reply-To: <200709150302.23743.arnd@arndb.de> References: <200709150221.57825.arnd@arndb.de> <1189811264.24878.3.camel@localhost.localdomain> <200709150302.23743.arnd@arndb.de> Content-Type: text/plain Date: Fri, 14 Sep 2007 18:36:21 -0500 Message-Id: <1189812981.24878.6.camel@localhost.localdomain> Mime-Version: 1.0 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, 2007-09-15 at 03:02 +0200, Arnd Bergmann wrote: > On Saturday 15 September 2007, Josh Boyer wrote: > > On Sat, 2007-09-15 at 02:21 +0200, Arnd Bergmann wrote: > > > Since the PPE on cell is an in-order core, it suffers significantly > > > from wrong instruction scheduling. This adds an Kconfig option that > > > enables passing -mtune=cell to gcc in order to generate object > > > code that runs well on cell. > > > > Which version of gcc supports that? > > > > gcc-4.3 will be the first official release that has everything in it, > and I think 4.1 has some parts. However, there are many patched gcc > versions in various distributions, so I tried to avoid being too > specific about the version here. > > Of course, on gcc versions that don't support -mtune=cell, the > Kconfig option does not make a difference. Sure. I was just wondering if mentioning the first official GCC version in the Kconfig description would help prevent users from selecting the option for GCCs that don't support it and then being confused later when nothing happens. Your call though. josh