From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by nuthatch.gentoo.org with esmtp (Exim 4.62) (envelope-from ) id 1HbcAZ-0008VN-0i for garchives@archives.gentoo.org; Wed, 11 Apr 2007 12:43:27 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.14.0/8.14.0) with SMTP id l3BCgEst015567; Wed, 11 Apr 2007 12:42:14 GMT Received: from nz-out-0506.google.com (nz-out-0506.google.com [64.233.162.237]) by robin.gentoo.org (8.14.0/8.14.0) with ESMTP id l3BCbnHt010621 for ; Wed, 11 Apr 2007 12:37:50 GMT Received: by nz-out-0506.google.com with SMTP id s1so118315nze for ; Wed, 11 Apr 2007 05:37:49 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=fZSsfIiAc57Gpc6lVLWVdNSWGiwdPI/XJ6yKPjHjdV9qVPpZDi5CMECgCTVx617ckp8FoD5Lf56nBgnsPTRmS+PvaQQAYpA7BVQSNxx/icVKO0R6O/lhlUzhVm+Mf7EQHW6xn6cSd2swicyT0NkDYHOOcsabEWRgmu0xfF/gC5s= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=fwpDgKqn1C5k8+LXx0E/OubJ4pr47v1/5kb5Fe3nSG/7OW/sdL9JvX713Ujxn7IK+KOSc9IosHqJvUi5jf8+qfx6aBd9sjeAAxeFV8Xp6WL17hBtGW/SvSqdvLC2kwsJq/mkPjl+D779I2avL23BNuEPo6a4gpBMqddtjsSfoTs= Received: by 10.115.61.1 with SMTP id o1mr248446wak.1176295069151; Wed, 11 Apr 2007 05:37:49 -0700 (PDT) Received: by 10.115.47.13 with HTTP; Wed, 11 Apr 2007 05:37:49 -0700 (PDT) Message-ID: <2fcf3fa50704110537j30677125h360e882281c9294d@mail.gmail.com> Date: Wed, 11 Apr 2007 08:37:49 -0400 From: "Francisco Rivas" To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Re: CFLAGS "...-O3 -pipe" vs "...O2 " In-Reply-To: <200704111345.04546.bo.andresen@zlin.dk> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_10948_28118471.1176295069063" References: <410166.43467.qm@web31703.mail.mud.yahoo.com> <200704111208.59191.bo.andresen@zlin.dk> <461CBEEB.7080407@ilievnet.com> <200704111345.04546.bo.andresen@zlin.dk> X-Archives-Salt: 40cc73ce-6493-4af8-96dd-781e5baf58ee X-Archives-Hash: b64ec810f7d0556fd87dd309b5cc400d ------=_Part_10948_28118471.1176295069063 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi all.. I think what -O3 is not _dangerous_ when you know how to use, a few posts ago someone mentioned not all of packages can be compiled using -O3, if I a= m not wrong was GCC and OpenOffice.org. The thing is: -O3 is not a _damage_ is an carefully flag to compile for som= e packages.. In some webpages I people said : ".. -O3 is not used by developer because come troubles when you want to do a debug..". But: http://www.nersc.gov/vendor_docs/intel/f_ug2/dbg_opt.htm, http://linuxgazette.net/121/hegde.html, http://publib.boulder.ibm.com/infocenter/macxhelp/v6v81/index.jsp?topic=3D/= com.ibm.xlf81m.doc/pgs/ug42.htm . "...The following setting is the "Optimizations". You shouldn't use O3 as i= t takes longer to compile, the generated code will be sometimes faster, sometimes slower and almost always larger. For example, a program that was compiled with the O2 level of optimization is 250KB large and is quite fast= , the same program compiled with the O3 level of optimization can take more time to compile, produce a larger binary, depending on the code, even 500-700KB large and it can be slower or faster. Therefore, the O3 optimization level isn't recommended. Use O2 if you need the best optimization without adding the risk of obtaining large binaries, which nee= d a long time to be loaded before being executed and are not always faster...= " take of http://www.softpedia.com/reviews/linux/Gentoo-Review-20543.shtml. On 4/11/07, Bo =D8rsted Andresen wrote: > > On Wednesday 11 April 2007 12:56:43 Daniel Iliev wrote: > > Sorry, I don't get it. Perhaps it is my poor English but I couldn't > > understand two things: > > - Is -O3 supported by Gentoo or not? > > -O3 is supported by Gentoo. > > > - What's the special thing about Gentoo ebuilds that makes -O3 > dangerous? > > No no. The special thing about Gentoo ebuilds is that -O3 in make.conf is > safe > for all packages because those packages for which -O3 isn't safe are > replacing it with -O2 in the ebuilds (or eclasses). > > -- > Bo Andresen > > --=20 ['Cause without love I won't survive, I love you]. I Francisco Rivas 2.6.19-gentoo-r5 x86 udev v087 gnome 2.16.2 xorg-x11-7.1 hotplug v20040923-r2 e-mail : fjrivas@uc.edu.ve msn : taken2k4@gmail.com -----BEGIN GEEK CODE BLOCK----- Version: 3.1 GCS/E/IT/MU d-(+)@ s++: a-- C++++>++++ ULSC*()>+++ P+(++)>+++ L++(+++)>++++ !E--- W+>++ !N* !o-(--)>-- K--? !w--- !O !M !V PS@ !PE@ Y> PGP t 5 X R+>+ tv- b DI D G e++>+++ h-> r++>+++ y- ------END GEEK CODE BLOCK------ ------=_Part_10948_28118471.1176295069063 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Hi all..

I think what -O3 is not _dangerous_ when you know how to u= se, a few posts ago someone mentioned not all of packages can be compiled u= sing -O3, if I am not wrong was GCC and OpenOffice.org.

The thing is= : -O3 is not a _damage_ is an carefully flag to compile for some packages..= =20

In some webpages I people said : ".. -O3 is not used by develo= per because come troubles when you want to do a debug..".

But:=
  http://www.nersc.gov/vendor_docs/intel/f_ug2/dbg_opt.htm,
 http://linuxgazette.net/121= /hegde.html,   http://publib.boulder.ibm.com/infocenter/macxhelp/v6v81/index.jsp?topic=3D/= com.ibm.xlf81m.doc/pgs/ug42.htm.

"...The following setting = is the "Optimizations". You shouldn't use O3 as it takes longer to compile, the generated code will be sometimes faster, sometimes slower and almost always larger. For example, a program that was compiled with the O2 level of optimization is 250KB large and is quite fast, the same program compiled with the O3 level of optimization can take more time to compile, produce a larger binary, depending on the code, even 500-700KB large and it can be slower or faster. Therefore, the O3 optimization level isn't recommended. Use O2 if you need the best optimization without adding the risk of obtaining large binaries, which need a long time to be loaded before being executed and are not always faster..." take of http://www.softpedia.= com/reviews/linux/Gentoo-Review-20543.shtml.


On 4/11/07, Bo =D8rsted Andresen <bo.andresen@zlin.dk> wrote:
On Wednesday 11 April 2007 12:56:43 Daniel Iliev wrote:
> Sorry, I do= n't get it. Perhaps it is my poor English but I couldn't
> un= derstand two things:
>  - Is -O3 supported by Gentoo or not= ?

-O3 is supported by Gentoo.

>  - What's the special= thing about Gentoo ebuilds that makes -O3 dangerous?

No no. The spe= cial thing about Gentoo ebuilds is that -O3 in make.conf is safe
for all= packages because those packages for which -O3 isn't safe are
replacing it with -O2 in the ebuilds (or eclasses).

--
Bo And= resen




--
['Caus= e without love I won't survive, I love you]. I

Francisco Rivas
2.6.19-gentoo-r5 x86
udev v087 gnome 2.16.2
xorg-x11-7.1 hotplug= v20040923-r2
e-mail : fjrivas@uc.e= du.ve
msn : taken2k4@gmail.com

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GCS/E/IT/MU = d-(+)@ s++: a-- C++++>++++ ULSC*()>+++ P+(++)>+++ L++(+++)>++++= !E--- W+>++ !N* !o-(--)>-- K--? !w--- !O !M !V PS@ !PE@ Y> PGP t = 5 X R+>+ tv- b DI D G e++>+++ h-> r++>+++ y-
------END GEEK CODE BLOCK------ ------=_Part_10948_28118471.1176295069063-- -- gentoo-user@gentoo.org mailing list