> On Sat, 10 Oct 1998, Ragnar Hojland wrote:
>
> > Well, some days ago I posted about a frozen 2.1.124. So I tried everything
> > back and forth trying to reproduce the lockup. Ended up playing with crashme
> > If you compile crashme with egcs 1.1b, with -O6 -g, and run it (obviously
> > as non root), with +2000.0 7191 2 , it locks up. Why the -O6 makes a
> > difference, I have no idea.. anyone mind illustrating me?
>
> egcs has a few bugs that can lead to miscompilation with optimizations > -O2
>
> Use -O2 rather than -O6; shouldn't be much slower, but more reliable.
Also anything >-O2 includes -finline-functions which makes gcc inline
functions without being told to. Some parts of the kernel are explicitely
tuned to keep specific functions out of line to generate better code and
to lower the register pressure on x86, -finline-functions kills these
optimizations. It will also make the kernel bigger which translates to
slower code because the caches are less effectively used.
-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/