Re: Why does C3 CPU downgrade in kernel 2.4.20?

From: Dave Jones (
Date: Tue Dec 10 2002 - 00:52:15 EST

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
I'm not sure about the alignment flags. I've been meaning to look
into that myself...


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