From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 3963E1381F4 for ; Fri, 17 Aug 2012 21:08:51 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 0D2FAE06C5; Fri, 17 Aug 2012 21:08:23 +0000 (UTC) Received: from out5-smtp.messagingengine.com (out5-smtp.messagingengine.com [66.111.4.29]) by pigeon.gentoo.org (Postfix) with ESMTP id E118AE0691 for ; Fri, 17 Aug 2012 21:05:55 +0000 (UTC) Received: from compute1.internal (compute1.nyi.mail.srv.osa [10.202.2.41]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id 9B1DD20AA7 for ; Fri, 17 Aug 2012 17:05:55 -0400 (EDT) Received: from frontend1.nyi.mail.srv.osa ([10.202.2.160]) by compute1.internal (MEProxy); Fri, 17 Aug 2012 17:05:55 -0400 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=binarywings.net; h=message-id:date:from:mime-version:to:subject:references :in-reply-to:content-type; s=mesmtp; bh=5AqNQLuF7fLnsePRqC0MaVxu tQs=; b=mUT77UwWUHIJhsYwbqyfVsIVR+luM0MKhihnJ/ho4ivOTF7Wa/7hbUVk qUaABzZUma4Hq0hGLPBNCcyepZFMbsr8AxyXTAF3bDWzYF9Obn+H4Z+Th1p2Uwkn tL2mpEs8drogh6wPxs+vNI83T08ivFsY1bOblMia6RnLd7JdVu8= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=message-id:date:from:mime-version:to :subject:references:in-reply-to:content-type; s=smtpout; bh=5AqN QLuF7fLnsePRqC0MaVxutQs=; b=mxuVL8z0+bWbJNhV2nfkwzIXs8e0zDcxEgeB AEg9bzLRBvS3RBKWujkTXSpSmhATtdPC0TNdbLRBE3aefkFknkLhrQkiBmaeDQVd a3fT3MKCfnVanJiy4cXCc9wQnQnQhGHFsTrjdRk0FWCenNOllFZUa81z3vDNMzOh 8XvIfIw= X-Sasl-enc: v615DFKZiHoE+z494IW4Qpc9sWUc26JItqS+L44WWpMq 1345237554 Received: from [10.216.119.237] (unknown [46.115.53.119]) by mail.messagingengine.com (Postfix) with ESMTPA id 6893D8E01FC for ; Fri, 17 Aug 2012 17:05:54 -0400 (EDT) Message-ID: <502EB22B.7000304@binarywings.net> Date: Fri, 17 Aug 2012 23:05:47 +0200 From: Florian Philipp User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.6esrpre) Gecko/20120804 Thunderbird/10.0.6 Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] common flags for 2 cpu? References: <502E4CCA.3070208@binarywings.net> In-Reply-To: X-Enigmail-Version: 1.3.5 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigF094B76AC7FF1737769BC86B" X-Archives-Salt: ac3e5a86-b836-4ae7-8810-3481bd73ac94 X-Archives-Hash: 6447c1f3cbf84c2608586356bed53d5a This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigF094B76AC7FF1737769BC86B Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Am 17.08.2012 19:57, schrieb Jorge Almeida: > On Fri, Aug 17, 2012 at 2:53 PM, Florian Philipp wrote: >> Am 17.08.2012 10:58, schrieb Jorge Almeida: >>> >>> 1) Is this strategy right? If so, any other flags to add? (or any >>> flags to remove from the list?) >>> >>> 2) The --param flags are the ones of the computer that will do the >>> compiling. I'm guessing the produced binaries are compatible with cpu= >>> with different --param flags. Is this right? >>> >>> TIA >>> >>> Jorge Almeida >>> >> >> 1) Yes. But as you can see, -march=3Dprescott is basically a subset of= >> atom. In fact, before there was a -march=3Datom option, prescott was t= he >> best flag for atoms. I think you can avoid some hassle by simply >> enabling "-march=3Dprescott --param l1-cache-line-size=3D64 --param >> l2-cache-size=3D512". >> >> 2) Yes, the param flags do not affect compatibility. Using the lower >> value will probably be better but this is just an educated guess. >> >=20 > What about: >=20 > CFLAGS=3D"-O2 -pipe -fomit-frame-pointer -march=3Dprescott -mtune=3Dato= m --param > l1-cache-size=3D16 --param l1-cache-line-size=3D64 --param l2-cache-siz= e=3D1024" >=20 > If prescott were exactly a subset of atom, this would yield the best of= both > worlds. Can it still be safe? >=20 > I read in http://forums.gentoo.org/viewtopic-t-895104.html : > atom > Intel Atom CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3 > instruction set support. >=20 > Does this mean that these flags are pulled by -mtune=3Datom, or do we n= eed to > ask for them explicitly? The WiKi shows how to find which flags are pul= led by > -march=3Dnative, but not the other cases. >=20 > Thanks >=20 > Jorge Almeida >=20 Oh, sorry, I didn't think of the second generation atoms. I guess your newer atom is a bit more different from prescott than the one I talked about. Anyway, using -march=3Dprescott is still viable. It just means you= lose a bit more in terms of usable SSE extensions on your atom. Your CFLAGS look good to me. They won't pull in anything that your prescott cannot handle. Regards, Florian Philipp --------------enigF094B76AC7FF1737769BC86B Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEUEARECAAYFAlAusi8ACgkQqs4uOUlOuU/kJQCfZ/cIwl+nwaj3+5iR8VfMiWll mzMAkQHHDEozc/uG7ij2Ust5w91LIU8= =gQNL -----END PGP SIGNATURE----- --------------enigF094B76AC7FF1737769BC86B--