From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from fed1rmmtao02.cox.net (fed1rmmtao02.cox.net [68.230.241.37]) by ozlabs.org (Postfix) with ESMTP id E994567AC6 for ; Fri, 6 May 2005 00:23:56 +1000 (EST) Date: Thu, 5 May 2005 07:23:54 -0700 From: Tom Rini To: Kumar Gala Message-ID: <20050505142354.GZ1221@smtp.west.cox.net> References: <7de437cded3ef3b030898889bf65e8c9@embeddededge.com> <49ea49620ccd32ef3032da76db24ad5d@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <49ea49620ccd32ef3032da76db24ad5d@freescale.com> Cc: linuxppc-dev@ozlabs.org Subject: Re: [PATCH] Set cpu explicitly in kernel compiles List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, May 05, 2005 at 09:00:50AM -0500, Kumar Gala wrote: > > On May 5, 2005, at 7:24 AM, Dan Malek wrote: > > > > > > >On May 5, 2005, at 1:22 AM, Paul Mackerras wrote: > > > If you think we should have -mcpu=xxx on the command line for 4xx, > > > 44x, 8xx, etc., then that's fine, but that is a separate problem > >from > > > what my patch was addressing (one which my patch might make it > >easier > > > to fix, though). > > > >I think that is exactly what we want, although I don't know how that is > > separate from the patch you sent.? My original comment was the patch > > fixes the problem for only one of the cpu cores, not all of them.? > >Which > > then led into the subsequent suggestion of making the biarch work > > like the past compilers, and we must specific the flags for POWER4 > > instead of the other way around.? Without explicit -mcpu flags, the > > existing compiler behavior is just fine .....? but, I guess I'd be > >standing > > in the way of progress to want this :-) > > I agree with Dan here. I think we should go ahead and extend the patch > to set -mcpu and -mtune flags for the list of processors we have in > "Processor Type". If I'm building a kernel for e500 or 4xx I might as > well get a kernel that is tuned a bit more for the subarch. This is fine. > Additionally, there should be some expert override ability, so if I > really want to do -mcpu=7455 -mtune=7455 I can. Gack, no! It's quite a pain to go from CONFIG_FOO="string" into useable Makefile bits that the one we did have back in 2.4 is gone. That also implies gcc finally knows something about these cores that might be useful, which I don't think is the case, nor is it likely to be. But if we did want it, we'd probably go the route x86 has. -- Tom Rini http://gate.crashing.org/~trini/