FWIW, I've used

	makeoptions	COPTS="-O6 -Wall -m486 -malign-loops=2 -malign-jumps=2 -malign-functions=2"

for kernels since, I think, before the 1.2 release.  Works fine for
me.  Super-aligning might help a little more. ``Appendix H''-style  
P5 scheduling is likely to help even more.


Last I looked at the gcc internals, I think  -O3 or -O4 was the actual
effective limit: by that point, all the optimizations avaliable are
turned on, and higher values of -On have no additional effect.

>Laine Stump wrote:
>> Has anyone experimented with the effects of building the kernel (and
>> libc, for that matter) with more agressive options? 1.2 builds with
>> simply "-O2". What about making it something like:
>>         -O6 -fomit-frame-pointer -m486

>I compile all of my kernels (for the past 6 months or so) with the
>Pentium version of gcc, with -O3 -fomit-frame-pointer -mpentium 
>(aggressive enough for you? :)


I seem to remember that Bruce Evans reported that using
-fomit-frame-pointer to compile FreeBSD kernels caused kernel crashes.
What version of a `pentium gcc' is the -mpentium used with, and where
did you get it from?