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- <li><em>date</em>: Wed Feb 11 22:57:31 2004</li>
- <li><em>from</em>: james at sumners.ath.cx (James Sumners)</li>
- <li><em>in-reply-to</em>: <1076557459.3920.828.camel@localhost></li>
- <li><em>references</em>: <<a href="msg00388.html">[email protected]</a>> <<a href="msg00404.html">[email protected]</a>> <1076557029.30236.818.camel@localhost> <1076557459.3920.828.camel@localhost></li>
- <li><em>subject</em>: -O3 vs. -O2 (was Re: [ale] sharing an experience....debian....)</li>
Here is a decent article with good
references about GCC and the optimization
flags though: <a rel="nofollow" href="http://freshmeat.net/articles/view/730/";>http://freshmeat.net/articles/view/730/</a>
On 11 Feb 2004 22:44:19 -0500
Jeff Hubbs <hbbs at comcast.net> wrote:
> There's another reason why I ask. I frequently install Gentoo on slow
> machines because a) I want to wring every last bit of performance I can
> out of the hardware available and b) I'm not under time pressure to do
> so :)
>
> But, according to this, in doing so and accepting the -O3 optimization
> suggested, I may only be hurting myself, ESPECIALLY if after building
> gcc, glibc, etc. in the bootstrap phase with -O3 and subsequently
> compiling everything else with that gcc, it might be taking m hours
> (days?) longer than necessary.
>
> I'd run tests. but I'd better do it on a CPU from this century or it'll
> take so long I'll forget what I'm testing.
>
> - Jeff
>
> On Wed, 2004-02-11 at 22:37, Jeff Hubbs wrote:
> > Can someone explain to me why the -O3 optimization would make programs
> > run *slower*? In asking, I'm not trying to cast aspersions or challenge
> > the assertion, I'm really only just trying to ask how this is so.
> >
> > - Jeff
> >
> > On Wed, 2004-02-11 at 19:23, James Sumners wrote:
> > > Stupid exmh didn't send this with the correct From: address earlier today.
> > >
> > > >From the November 04, 2003 Debian news
> > > (<a rel="nofollow" href="http://lists.debian.org/debian-news/debian-news-2003/msg00056.html";>http://lists.debian.org/debian-news/debian-news-2003/msg00056.html</a>):
> > >
> > > --- Begin Quote ---
> > > Debian faster than Gentoo? Matt Garman [2]wondered why his C++
> > > program ran dramatically slower when compiled on a Gentoo machine than
> > > when compiled with Debian Sid. He later [3]reported that recompiling
> > > the Gentoo C++ libraries with less aggressive optimization flags (-O2
> > > instead of -O3) eliminated the speed difference. Matt also [4]added
> > > that Debian and other distributions are conservative, but set up by
> > > very experienced people.
> > >
> > > 2. <a rel="nofollow" href="http://article.gmane.org/gmane.linux.gentoo.user/50924";>http://article.gmane.org/gmane.linux.gentoo.user/50924</a>
> > > 3. <a rel="nofollow" href="http://article.gmane.org/gmane.linux.gentoo.user/50973";>http://article.gmane.org/gmane.linux.gentoo.user/50973</a>
> > > 4. <a rel="nofollow" href="http://article.gmane.org/gmane.linux.gentoo.user/50953";>http://article.gmane.org/gmane.linux.gentoo.user/50953</a>
> > > --- End Quote ---
> > >
> > > Basically, Red Hat (Fedora) packages are typically compiled in a
> > > haphazard
> > > fashion in relation to the other packages in the distribution. The
> > > packages in Debian go through an arduous testing process and are built
> > > according to rather strict rules.
> > >
> > > James Sumners
> > >
> > > On Wed, 11 Feb 2004 13:12:30 -0500
> > > Keith Morris - IQ <keith at iqtv.com> wrote:
> > >
> > > > Hi all, just wanted to share a quick experience and get your opinions if
> > > > you are willing.
> > > >
> > > > I have been using linux off and on since Redhat 5.1 and exclusively for
> > > > the last 3 years at home. I have pretty much been a redhat man with no
> > > > complaints. I use Fedora Core 1 on my 2 main machines at home (both
> > > > 1.6GHz). Well, recently I got a PIII 866 to play with and installed FC1
> > > > on it and the speed was really quite sluggish. Played with a few more
> > > > distros which I wasn't really happy with. Well, I've always been afraid
> > > > of Debian with it's infamous hell-installer, but with it's new Beta
> > > > installer, I decided to try it.
> > > >
> > > > After a pretty painless net-install, I was totally shocked with the
> > > > speed of Debian. Easily twice as fast as Fedora on the 866 using the
> > > > *SAME* software (Gnome 2.4, KDE 3.1.5, OpenOffice, Evolution, XFT
> > > > support, antialiasing, etc.) I still have not gotten the sound working,
> > > > but believe that I will be able to (with a few posts to the ALE list :))
> > > > The only main difference is that I formatted / with reiserfs instead of
> > > > ext3 with FC1.
> > > >
> > > > I was wondering if anyone could guess why debian would be sooooo much
> > > > faster with basically the same "Desktop" type of configuration? Do many
> > > > of you use Debian?
> > > >
> > > > I will probably stick with Debian on this machine to learn about the
> > > > different ins-and-outs. I absolutely *love* apt-get for debian. I have
> > > > used it with rpms on redhat, but it seems better with debs...dunno...
> > > >
> > > > Anyway, thanks for letting me share.
> > > >
> > > > Keith Morris
> > > > Creative Director
> > > > Design / Effects
> > > > IQ television group
> > > > <a rel="nofollow" href="http://www.iqtv.com";>http://www.iqtv.com</a>
> > > >
> > > >
> > > > _______________________________________________
> > > > Ale mailing list
> > > > Ale at ale.org
> > > > <a rel="nofollow" href="http://www.ale.org/mailman/listinfo/ale";>http://www.ale.org/mailman/listinfo/ale</a>
> --
> Jeff Hubbs <hbbs at comcast.net>
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> <a rel="nofollow" href="http://www.ale.org/mailman/listinfo/ale";>http://www.ale.org/mailman/listinfo/ale</a>
--
I used to be interested in Windows NT, but the more I see of it the more it
looks like traditional Windows with a stabler kernel. I don't find anything
technically interesting there. In my opinion MS is a lot better at making money
than it is at making good operating systems. -- Linus Torvalds
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<ul><li><strong>References</strong>:
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<li><strong><a name="00388" href="msg00388.html">[ale] sharing an experience....debian....</a></strong>
<ul><li><em>From:</em> keith at iqtv.com (Keith Morris - IQ)</li></ul></li>
<li><strong><a name="00404" href="msg00404.html">[ale] sharing an experience....debian....</a></strong>
<ul><li><em>From:</em> james at sumners.ath.cx (James Sumners)</li></ul></li>
<li><strong><a name="00412" href="msg00412.html">-O3 vs. -O2 (was Re: [ale] sharing an experience....debian....)</a></strong>
<ul><li><em>From:</em> hbbs at comcast.net (Jeff Hubbs)</li></ul></li>
<li><strong><a name="00413" href="msg00413.html">-O3 vs. -O2 (was Re: [ale] sharing an experience....debian....)</a></strong>
<ul><li><em>From:</em> hbbs at comcast.net (Jeff Hubbs)</li></ul></li>
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