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    SubjectRe: -Os versus -O2
    On Sun, Jun 24, 2007 at 09:34:05PM -0400, Jeff Garzik wrote:
    > Adrian Bunk wrote:
    >> The interesting questions are:
    >> Does -Os still sometimes generate faster code with gcc 4.2?
    >> If yes, why?
    > Smaller code can mean fewer page faults, fewer cache invalidations, etc.
    > It's not just a matter of compiler code generation, gotta look at the whole
    > picture.

    Sure, but my point is that if the kernel is considered special and the
    best optimization for the kernel is therefore between -Os and -O2, we
    should try to find this point of best optimization.

    This should address Arjans point that -Os might not be best choice for
    best performance (and it's actually our fault if gcc generates stupid
    but small code when we use -Os).

    > Jeff



    "Is there not promise of rain?" Ling Tan asked suddenly out
    of the darkness. There had been need of rain for many days.
    "Only a promise," Lao Er said.
    Pearl S. Buck - Dragon Seed

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