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    SubjectRe: CONFIG_TINY
    On Thu, Oct 31, 2002 at 07:33:01AM -0700, Tom Rini wrote:
    > On Thu, Oct 31, 2002 at 12:33:10AM -0500, Mark Mielke wrote:
    > > On Wed, Oct 30, 2002 at 06:10:02PM -0700, Tom Rini wrote:
    > > > On Thu, Oct 31, 2002 at 01:53:14AM +0100, Adrian Bunk wrote:
    > > > > could you try to use "-Os" instead of "-O2" as gcc optimization option
    > > > > when CONFIG_TINY is enabled? Something like the following (completely
    > > > > untested) patch:
    > > > -Os can produce larger binaries, keep in mind. If we're going to go
    > > > this route, how about something generally useful, and allow for general
    > > > optimization level / additional CFLAGS to be added.
    > >
    > > Sure CFLAGS should be configurable, but CONFIG_TINY should always prefer
    > > -Os over -O2. From 'man gcc':
    > >
    > > -Os Optimize for size. -Os enables all -O2 optimizations that do not
    > > typically increase code size. It also performs further optimiza-
    > > tions designed to reduce code size.
    > >
    > > If gcc regularly generates larger code with -Os the answer is to talk to
    > > the gcc people, not to avoid using -Os...
    > It's not that it does regularly, it's that it can, and if it does, it's
    > not really a gcc bug from what I recall. So I don't think CONFIG_TINY
    > should prefer -Os over -O2 but instead we should just ask the user what
    > level of optimization they want. Remember, one of the real important
    > parts of embedded systems is flexibility.

    Thank you. This is exactly why in the last CONFIG_TINY thread I made
    it clear that a one-size-fits-all option is not all that helpful for
    serious embedded systems designers.

    Collecting these parameters in a single tweaks.h file and perhaps using
    things like CONFIG_TINY, CONFIG_DESKTOP, CONFIG_FOO as profile selectors
    into tweaks.h would be a lot more effective. His collection of
    (hopefully) size-optimizing tweaks can all be selected via CONFIG_TINY,
    but have them collected at a single point like tweaks.h such that they
    can be individually modified by an end system integrator.

    Matt Porter
    This is Linux Country. On a quiet night, you can hear Windows reboot.
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