Messages in this thread | | | Date | Tue, 10 Dec 2002 05:52:15 +0000 | From | Dave Jones <> | Subject | Re: Why does C3 CPU downgrade in kernel 2.4.20? |
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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
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