From: Dave Jones <davej@codemonkey.org.uk>
To: Joseph <jospehchan@yahoo.com.tw>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Why does C3 CPU downgrade in kernel 2.4.20?
Date: Tue, 10 Dec 2002 05:52:15 +0000 [thread overview]
Message-ID: <20021210055215.GA9124@suse.de> (raw)
In-Reply-To: <009f01c2a000$f38885d0$3716a8c0@taipei.via.com.tw>
On Tue, Dec 10, 2002 at 12:02:25PM +0800, Joseph wrote:
> Hi all,
> I rebuilt the 2.4.20 kernel with C3 CPU and found it been downgraded to
> i486.
> And I check the file, linux/arch/i386/Makefile, in both of 2.4.19 and
> 2.4.20 kernels.
> In 2.4.19, the CFLAGS adds "-march=i586".
> But in 2.4.20, the CFLAGS adds
> "-march=i486 -malign-functions=0 -malign-jumps=0 -malign-loops=0".
> Why do this? Could anybody explain this to me?
I believe someone (Jeff Garzik?) benchmarked gcc code generation,
and the C3 executed code scheduled for a 486 faster than it did for
-m586
I'm not sure about the alignment flags. I've been meaning to look
into that myself...
Dave
next prev parent reply other threads:[~2002-12-10 5:44 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-10 4:02 Why does C3 CPU downgrade in kernel 2.4.20? Joseph
2002-12-10 5:52 ` Dave Jones [this message]
2002-12-10 7:22 ` Daniel Egger
2002-12-10 7:24 ` Dave Jones
2002-12-10 7:53 ` Daniel Egger
2002-12-10 12:40 ` Juan Quintela
2002-12-10 15:40 ` Daniel Egger
2002-12-10 16:51 ` Alan Cox
2002-12-10 19:39 ` Daniel Egger
2002-12-10 20:17 ` Jeff Garzik
2002-12-10 21:24 ` Alan Cox
2002-12-11 18:51 ` Bill Davidsen
2002-12-11 19:14 ` Dave Jones
2002-12-11 19:42 ` Jeff Garzik
2002-12-11 19:51 ` Joel Jaeggli
2002-12-12 9:17 ` Joseph
2002-12-12 13:33 ` Dave Jones
2002-12-13 6:55 ` Joseph
2002-12-13 11:04 ` Daniel Egger
2002-12-13 11:57 ` Dave Jones
2002-12-11 21:00 ` Alan Cox
2002-12-12 10:19 ` P
2002-12-11 13:19 ` Denis Vlasenko
2002-12-11 10:58 ` Dave Jones
2002-12-11 19:09 ` Denis Vlasenko
2002-12-11 14:59 ` Dave Jones
2002-12-12 18:09 ` Pavel Machek
2002-12-14 16:46 ` Denis Vlasenko
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