lkml.org 
[lkml]   [2002]   [Dec]   [10]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
    /
    DateTue, 10 Dec 2002 05:52:15 +0000
    FromDave Jones <>
    SubjectRe: Why does C3 CPU downgrade in kernel 2.4.20?
    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
    
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at  http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at  http://www.tux.org/lkml/
    
    
    \
     
     \ /
      Last update: 2005-03-22 13:31    [from the cache]
    ©2003-2008