From: Chris White <chriswhite@gentoo.org>
To: Margit Schubert-While <margitsw@t-online.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: 2.6.13/14 x86 Makefile - Pentiums penalized ?
Date: Wed, 14 Sep 2005 14:14:02 +0900 [thread overview]
Message-ID: <200509141414.08343.chriswhite@gentoo.org> (raw)
In-Reply-To: <5.1.0.14.2.20050913075517.0259c498@pop.t-online.de>
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On Tuesday 13 September 2005 15:04, Margit Schubert-While wrote:
> In arch/i386/makefile we have :
> cflags-$(CONFIG_MPENTIUMII) += -march=i686 $(call
> cc-option,-mtune=pentium2)
> cflags-$(CONFIG_MPENTIUMIII) += -march=i686 $(call
> cc-option,-mtune=pentium3)
> cflags-$(CONFIG_MPENTIUMM) += -march=i686 $(call
> cc-option,-mtune=pentium3)
> cflags-$(CONFIG_MPENTIUM4) += -march=i686 $(call
> cc-option,-mtune=pentium4)
>
> According to the gcc 3.x doc, the -mtune is not avaliable for i686
> and, indeed, with 3.3.5 no -mtune is generated/used (make V=1).
That's correct, gcc 3.4 started the -mtune flag. Chances are if you really
want the -mtune optimizations you're going to have to upgrade to gcc 3.4 or
greater.
> This, of course, heavily penalizes P4's (the notorious inc/dec).
Are you referring to cpu cycle counts? Is there certain code that causes the
kernel to perform that unfavorably by a large scale?
> Margit
Chris White
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next prev parent reply other threads:[~2005-09-13 20:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-13 6:04 Margit Schubert-While
2005-09-14 5:14 ` Chris White [this message]
2005-09-14 6:48 ` Zwane Mwaikambo
2005-09-14 6:59 ` Denis Vlasenko
2005-09-14 7:21 ` Zwane Mwaikambo
2005-09-14 7:51 ` Denis Vlasenko
2005-09-14 7:48 ` Margit Schubert-While
2005-09-14 7:54 ` Denis Vlasenko
2005-09-14 7:02 ` Margit Schubert-While
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