Messages in this thread | | | Date | Thu, 31 Oct 2002 10:04:20 -0700 | From | Tom Rini <> | Subject | Re: CONFIG_TINY |
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On Thu, Oct 31, 2002 at 11:51:13AM -0500, Mark Mielke wrote: > On Thu, Oct 31, 2002 at 07:33:01AM -0700, Tom Rini wrote: > > > 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. > > Not to stretch this point too long, but turning off inlined functions 'can' > make code bigger too. It usually doesn't. > > I have no problem with the other suggestion that CONFIG_TINY specify a > template for a set of build options, but if CONFIG_TINY is used (either > as an option, or a template of options) -Os should always be preferred > over -O2. Whether the user can still override this or not is a different > issue from whether -Os should be preferred over -O2 when CONFIG_TINY is > specified. > > Or specified more clearly: If the compiler optimization flag is configurable, > choosing CONFIG_TINY should default the optimization flag to -Os before it > defaults the optimization flag to -O2.
You're still missing the point of flexibility remark. Changing the optimization level has nothing to do with CONFIG_TINY, and is a generally useful option, and should be done seperate from CONFIG_TINY. In fact people seem to be getting the wrong idea about CONFIG_TINY. We don't need a CONFIG_TINY, we need CONFIG_FINE_TUNE. Different 'tiny' projects need different things. And when you take into account that the embedded world is a whole lot of !i386, the fact that -Os hasn't been as well tested on !i386, you introduce the possibility of compiler bugs sneaking in as well.
In other words, s/CONFIG_TINY/CONFIG_FINE_TUNE, and ask about anything / everything which might want to be tuned up. Then this becomes a truely useful set of options, since as Alan pointed out in one of the earlier CONFIG_TINY threads, his Athlon could benefit from some of these 'tiny' options too.
-- Tom Rini (TR1265) http://gate.crashing.org/~trini/ - 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/
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