Em Sat, Dec 21, 2002 at 07:20:28PM -0600, scott thomason escreveu:
> On Saturday 21 December 2002 04:10 pm, folkert@vanheusden.com wrote:
> > > > Is there any risk using -O3 instead of -O2 to compile the
> > > > kernel, and why?
> > >
> > > * It might uncover subtle bugs that would otherwise not occur.
> >
> > I wonder: for the sake of performance and good use of the precious
> > clock- cycles, shouldn't there be made a start of fixing those
> > bugs? Assuming that the bugs you're talking about are not
> > compiler-bugs, they *are* bugs in the code that should be fixed,
> > shouldn't they?
> >
> > > * Compiling with unusual options means that less people will know
> > > about any problems it causes you.
> >
> > So, let's make it -O6 per default for 2.7.x/3.1.x?
>
> Let's not. I'd rather have the best kernel developers concentrating on
> finishing important kernel features rather than digging their way out
> of esoteric optimizer debugging sessions only to find it was a flaw
> in gcc. The difference in performance boost between -O2 and greater
> levels isn't usually enough to make a significant impact, not as
> significant as the introduction of important new features, for
> example.
Sometimes even _reducing_ the optimization for performance level makes it
faster, try with -Os. And this was already discussed here and elsewhere,
reading the archives would help a lot avoiding adding more noise to the list.
- Arnaldo
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