From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 93-97-173-237.zone5.bethere.co.uk ([93.97.173.237] helo=tim.rpsys.net) by linuxtogo.org with esmtp (Exim 4.72) (envelope-from ) id 1Qlzb8-0003dG-CS for openembedded-core@lists.openembedded.org; Wed, 27 Jul 2011 10:36:10 +0200 Received: from localhost (localhost [127.0.0.1]) by tim.rpsys.net (8.13.6/8.13.8) with ESMTP id p6R8Vv8q028480 for ; Wed, 27 Jul 2011 09:31:57 +0100 Received: from tim.rpsys.net ([127.0.0.1]) by localhost (tim.rpsys.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 27332-04 for ; Wed, 27 Jul 2011 09:31:52 +0100 (BST) Received: from [192.168.3.10] ([192.168.3.10]) (authenticated bits=0) by tim.rpsys.net (8.13.6/8.13.8) with ESMTP id p6R8ViUD028474 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 27 Jul 2011 09:31:48 +0100 From: Richard Purdie To: Patches and discussions about the oe-core layer In-Reply-To: <7C3E3CE4-B2F1-4B53-9245-FC13D2DA6EEC@kernel.crashing.org> References: <346abefc87d21d0cc111ef87a6e48f40c5b6cb0b.1311683981.git.richard.purdie@linuxfoundation.org> <992efbf4ec3d7c55346953dbe82f9745590e64bf.1311683981.git.richard.purdie@linuxfoundation.org> <969FA904-0086-42FA-B605-07B74FB728B4@kernel.crashing.org> <1311688752.2344.238.camel@rex> <627CF4AB-F07D-4285-B31C-3C5631270420@kernel.crashing.org> <1311697113.2344.268.camel@rex> <7C3E3CE4-B2F1-4B53-9245-FC13D2DA6EEC@kernel.crashing.org> Date: Wed, 27 Jul 2011 09:31:33 +0100 Message-ID: <1311755493.2344.322.camel@rex> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 X-Virus-Scanned: amavisd-new at rpsys.net Subject: Re: [PATCH 3/3] Add basic PowerPC core tune config X-BeenThere: openembedded-core@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: Patches and discussions about the oe-core layer List-Id: Patches and discussions about the oe-core layer List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 Jul 2011 08:36:10 -0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit On Tue, 2011-07-26 at 17:03 -0500, Kumar Gala wrote: > On Jul 26, 2011, at 11:18 AM, Richard Purdie wrote: > > > On Tue, 2011-07-26 at 10:22 -0500, Kumar Gala wrote: > >> On Jul 26, 2011, at 8:59 AM, Richard Purdie wrote: > >> > >>> On Tue, 2011-07-26 at 08:47 -0500, Kumar Gala wrote: > >>>> On Jul 26, 2011, at 7:44 AM, Richard Purdie wrote: > >>>> > >>>>> Signed-off-by: Richard Purdie > >>>>> --- > >>>>> meta/conf/machine/include/powerpc/arch-powerpc.inc | 45 +++++++++++++++++++- > >>>>> meta/conf/machine/include/tune-ppc603e.inc | 12 ++++- > >>>>> meta/conf/machine/include/tune-ppce300c2.inc | 12 ++++- > >>>>> meta/conf/machine/include/tune-ppce500.inc | 13 ++++-- > >>>>> meta/conf/machine/include/tune-ppce500mc.inc | 12 ++++- > >>>>> meta/conf/machine/include/tune-ppce500v2.inc | 12 ++++- > >>>>> 6 files changed, 88 insertions(+), 18 deletions(-) > >>>> > >>>> One thing I'm wondering about as we do this is the ability to pass > >>>> --with-cpu to gcc & [e]glibc configure to pickup proper optimized cfgs > >>>> & libs for a given target. > >>> > >>> As far as I can tell, gcc 4.x has no --with-cpu option. We pass the > >>> correct march and mtune options to the compiler at runtime through > >>> CFLAGS and friends. > >> > >> Hmm, gcc still supports this: > >> > >> http://gcc.gnu.org/install/configure.html > >> > >> --with-cpu=cpu > >> --with-cpu-32=cpu > >> --with-cpu-64=cpu > >> Specify which cpu variant the compiler should generate code for by default. cpu will be used as the default value of the -mcpu= switch. This option is only supported on some targets, including ARM, i386, M68k, PowerPC, and SPARC. The --with-cpu-32 and --with-cpu-64 options specify separate default CPUs for 32-bit and 64-bit modes; these options are only supported for i386, x86-64 and PowerPC. > >> > >> http://gcc.gnu.org/install/specific.html > >> > >> powerpc-*-* > >> You can specify a default version for the -mcpu=cpu_type switch by using the configure option --with-cpu-cpu_type. > > > > I couldn't find that looking at the configure script :/. > > > > Anyhow, according to that page, its to "Specify which cpu variant the > > compiler should generate code for by default. cpu will be used as the > > default value of the -mcpu= switch". Since we always specify -mcpu when > > needed, I don't believe this is an issue for us as far as the build > > system goes. > > > > If you're talking about the gcc we build for the target, we should > > really encode all the cpu/tune options in there, not just part of the > > config so again, I don't think its appropriate to the way we use gcc. > > What about tool chains produced as part of a ADT, wouldn't it be useful for such as case? > > Seems like having ability to pass '--with-cpu' ends up being useful to set default for things like 32 vs 64-bit on multiple. ADT passes an environment script with all the appropriate flags contained within including tunings which --with-cpu doesn't help with so I'm not sure its so useful there. Cheers, Richard