From mboxrd@z Thu Jan 1 00:00:00 1970 From: ludo@gnu.org (Ludovic =?utf-8?Q?Court=C3=A8s?=) Subject: Re: [PATCH 2/2] gnu: zita-convolver: Drop the '-march=native' optimization. Date: Thu, 07 Jan 2016 14:20:50 +0100 Message-ID: <8737u9ttjh.fsf@gnu.org> References: <1452095330-14147-1-git-send-email-iyzsong@gmail.com> <874meq5s30.fsf@elephly.net> <87y4c2qbv9.fsf@member.fsf.org> <87ziwh4wfo.fsf@elephly.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:58516) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aHAUr-0003IX-7S for guix-devel@gnu.org; Thu, 07 Jan 2016 08:20:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aHAUm-000596-Th for guix-devel@gnu.org; Thu, 07 Jan 2016 08:20:57 -0500 In-Reply-To: <87ziwh4wfo.fsf@elephly.net> (Ricardo Wurmus's message of "Thu, 07 Jan 2016 09:37:31 +0100") List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org To: Ricardo Wurmus Cc: guix-devel@gnu.org Ricardo Wurmus skribis: > =E5=AE=8B=E6=96=87=E6=AD=A6 writes: > >> Ricardo Wurmus writes: >> >>>> + (snippet >>>> + ;; Don't optimize for a specific processor architectur= e. >>>> + '(substitute* "libs/Makefile" >>>> + (("^CXXFLAGS \\+=3D -march=3Dnative") ""))) >>>> + (modules '((guix build utils))) >>> >>> Is this to avoid that packages are optimised for the CPU of the build >>> slave? >> Yes, using that from hydra will crash guitarix for me. >> Same as: . > > Guitarix also crashes for me on i686 =E2=80=94 and I thought it was somet= hing to > do with my machine or the broken build of eigen. Eigen is a header-only library, so what matters is the optimization flags passed when building the software that uses Eigen. >>> If so, could we instead pass different optimisation flags for >>> different architectures? For a convolver I=E2=80=99d prefer to have *s= ome* >>> optimisation, even if it=E2=80=99s just the greatest common divisor. It=E2=80=99s likely that zita-convolver has -O2 or similar *in addition* to -march=3Dnative, because the latter is no substitute for the former. Could you check that in the makefiles? But yeah, the patch is a good idea anyway. Thanks, Ludo=E2=80=99.