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From: Jakub Jelinek <jakub@redhat.com>
To: Luigi Genoni <kernel@Expansa.sns.it>
Cc: "Paul G. Allen" <pgallen@randomlogic.com>,
	"Linux kernel developer's mailing list" 
	<linux-kernel@vger.kernel.org>
Subject: Re: gcc-2.95.3 vs gcc-3.0.4
Date: Mon, 25 Feb 2002 02:48:17 -0500	[thread overview]
Message-ID: <20020225024817.Q2434@devserv.devel.redhat.com> (raw)
In-Reply-To: <3C775FEF.BDA0253C@randomlogic.com> <Pine.LNX.4.44.0202250100540.15348-100000@Expansa.sns.it>
In-Reply-To: <Pine.LNX.4.44.0202250100540.15348-100000@Expansa.sns.it>; from kernel@Expansa.sns.it on Mon, Feb 25, 2002 at 01:07:42AM +0100

On Mon, Feb 25, 2002 at 01:07:42AM +0100, Luigi Genoni wrote:
> At this link:
> 
>  http://www.cs.utk.edu/~rwhaley/ATLAS/gcc30.html
> 
> you can find an interesting explanation why code compiled with gcc 3.0 is
> mostly slower than code compiled with gcc 2.95 on x86 CPUs (but it is
> really faster on other platforms like alpha and sparc64).
> 
> basically the main reasons semm to be the scheduler algorithm and the fpu
> stack handling, but I suggest to read the full study.
> 
> 
> I would be interested to know if this apply to gcc 3.1 too.

Well, concerning reg-stack, you can completely get away without it in 3.1 
by using -mfpmath=sse if you are targeting Pentium 3,4 or Athlon 4,xp,mp
(for float math, for higher precision only for Pentium 4).

	Jakub

  parent reply	other threads:[~2002-02-25  7:48 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-02-23  4:40 gcc-2.95.3 vs gcc-3.0.4 Justin Piszcz
2002-02-23  4:44 ` Larry McVoy
2002-02-23  5:13   ` Justin Piszcz
2002-02-23  5:22   ` Andrew Morton
2002-02-23  5:50     ` Richard Gooch
2002-02-23 10:31     ` Benny Sjostrand
2002-02-23 15:00     ` Martin Dalecki
2002-02-25  8:07     ` Simon Kirby
2002-02-25  8:15       ` David S. Miller
2002-02-25  8:32       ` David Rees
2002-02-25  9:32         ` Ian Castle
2002-02-25  9:52       ` Markus Schaber
2002-02-23  5:40 ` hugang
2002-02-23  5:56   ` Andrew Morton
2002-02-23  9:25     ` Paul G. Allen
2002-02-23 13:55       ` gmack
2002-02-23 15:43       ` bert hubert
2002-02-25  0:07       ` Luigi Genoni
2002-02-25  0:32         ` ANN: syscalltrack v0.7 released guy keren
2002-02-25  7:48         ` Jakub Jelinek [this message]
2002-02-25  9:46           ` gcc-2.95.3 vs gcc-3.0.4 Luigi Genoni
2002-02-25  9:59             ` Jakub Jelinek
2002-02-25 12:55               ` Jan Hubicka
2002-02-25 16:08 ` Juan Quintela

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