From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gate.tarent.de ([212.79.178.249] helo=ugs.tarent.de) by linuxtogo.org with esmtp (Exim 4.69) (envelope-from ) id 1OP9P3-0001hN-6e for openembedded-devel@lists.openembedded.org; Thu, 17 Jun 2010 09:20:51 +0200 Received: from localhost (localhost [127.0.0.1]) by ugs.tarent.de (Postfix) with ESMTP id C26E740008230 for ; Thu, 17 Jun 2010 09:16:11 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by ugs.tarent.de (Postfix) with ESMTP id B9FF3400057E9 for ; Thu, 17 Jun 2010 09:16:11 +0200 (CEST) X-Virus-Scanned: by amavisd-new-2.6.1 (20080629) (Debian) at tarent.de Received: from ugs.tarent.de ([127.0.0.1]) by localhost (ugs.tarent.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 2FqdZT0gpxfm for ; Thu, 17 Jun 2010 09:16:11 +0200 (CEST) Received: from [192.168.4.51] (entw2.tarent.buero [192.168.4.51]) by ugs.tarent.de (Postfix) with ESMTPSA id 7F97040008230 for ; Thu, 17 Jun 2010 09:16:11 +0200 (CEST) Message-ID: <4C19CC08.9040606@gmx.net> Date: Thu, 17 Jun 2010 09:17:28 +0200 From: Robert Schuster User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100423 Thunderbird/3.0.4 MIME-Version: 1.0 To: openembedded-devel@lists.openembedded.org References: <4C187CF6.5010401@gmx.net> <20100616090200.5c23b895@xora-desktop.xora.org.uk> <20100616175640.4d7795ff@xora-desktop.xora.org.uk> <4C19CA2D.4@gmx.net> In-Reply-To: <4C19CA2D.4@gmx.net> X-Enigmail-Version: 1.0.1 X-SA-Exim-Connect-IP: 212.79.178.249 X-SA-Exim-Mail-From: thebohemian@gmx.net X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on discovery X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=AWL,BAYES_00,HTML_MESSAGE, SPF_FAIL autolearn=no version=3.2.5 X-SA-Exim-Version: 4.2.1 (built Wed, 25 Jun 2008 17:20:07 +0000) X-SA-Exim-Scanned: Yes (on linuxtogo.org) X-Content-Filtered-By: Mailman/MimeDel 2.1.11 Subject: Re: [RFC] add ubuntu patch which adds atomic builtin support to gcc 4.3.[3 but also other microversions] X-BeenThere: openembedded-devel@lists.openembedded.org X-Mailman-Version: 2.1.11 Precedence: list Reply-To: openembedded-devel@lists.openembedded.org List-Id: Using the OpenEmbedded metadata to build Distributions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Jun 2010 07:20:51 -0000 X-Groupsio-MsgNum: 20225 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigB878D3A69B1434F10F412BBB" --------------enigB878D3A69B1434F10F412BBB Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi, just a few more words about the patches: - Ubuntu ARM used it for a long time, so its tested for a while - for x86/amd64 atomic operations intrinsics are available for a looong time, so all packages built for these arches where already under the effect of 'GCC atomic builtins are available'. Regards, Robert Am 17.06.2010 09:09, schrieb Robert Schuster: > Hi, > first of all. As Stefan pointed out the change was needed while working= > for Buglabs on OpenJDK support. So it was decided that the introduction= > of the mentioned GCC change is handled by Stefan Schmidt now. > > But I would like to elaborate on the side-effects of the patch. > > Am 16.06.2010 19:12, schrieb Khem Raj: > =20 >> Those applications are working fine and they will keep working fine as= >> long as you dont recompile them >> and you make sure that libgcc is updated then whenever you rebuild an >> application that uses the atomic >> builtins will start using them until then it should work without using= them. >> =20 >> =20 > Yes, already built and shipped applications are not affected at all. > It is only that when certain packages are built again with the new GCC,= > the package's binary > will be different although PR (and PV) did not change. The reason is > that most configure scripts check > for the availability of the GCC intrinsics. If they are found they make= > use of it, if not they either use a different implementation > (libatomic-ops for example) > or bring their own (software running on ARM Linux 2.6 can assume that > the neccessary kernel helpers exist and make use of them[0]) or silentl= y > disable > multithread support (that is the case for llvm 2.7). > > And already compiled software will also not magically pick up the > implementation found in libgcc because: > 1) it was not there before > 2) I am under the impression that at least some of the builtins are > actually macros and thus bits of machinecode are copied into each binar= y > using them. > > However as said. Stefan is now dealing with the issue. He has gotten tw= o > patches (one from Ubuntu, another one from the GCC 4.4 stable branch) > that we needed to get things going and is most likely checking the > effects they have. > > Regards, > Robert > > [0] - code like this can be found in many projects; search for > __kernel_dmb and __kernel_cmpxchg: > http://code.google.com/p/nativeclient/source/browse/trunk/src/native_cl= ient/src/include/linux/arm/atomic_ops.h?r=3D857 > =20 >> Maybe I am missing something it would be helpful if Robert could >> explain potential scenarios >> where it would break precompiled binaries. I don't see it. >> >> =20 >> =20 >>> Graeme >>> >>> _______________________________________________ >>> Openembedded-devel mailing list >>> Openembedded-devel@lists.openembedded.org >>> http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-deve= l >>> >>> =20 >>> =20 >> _______________________________________________ >> Openembedded-devel mailing list >> Openembedded-devel@lists.openembedded.org >> http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-devel= >> =20 >> =20 > > =20 > > > _______________________________________________ > Openembedded-devel mailing list > Openembedded-devel@lists.openembedded.org > http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-devel > =20 --------------enigB878D3A69B1434F10F412BBB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkwZzAgACgkQG9cfwmwwEto7GQCgg8mbqAPVdM1OFBZJhtss5tzl whgAmwVjo4cQ2rdJlKWj6vwHAAuwjETl =ZXa5 -----END PGP SIGNATURE----- --------------enigB878D3A69B1434F10F412BBB--