OK, couldn't wait any longer, so I just tried it
So, here's what I have done:
in /usr/src/linux/Makefile, I added '-march=athlon-xp' and changed '-02' for '-03' to HOSTCFLAGS so it looks like:
Code:
HOSTCFLAGS = -Wall -Wstrict-prototypes -march=athlon-xp -pipe -O3 -fomit-frame-pointer
I did the same changes to CFLAGS, so I now looks like:
Code:
CFLAGS := $(CPPFLAGS) -Wall -Wstrict-prototypes -march=athlon-xp -Wno-trigraphs -O3 \
-fno-strict-aliasing -fno-common
Now, the compiled kernel works perfectly, but I didn't check the speed gain (if there is any).
The resulting bzImage is bigger (for the same config file) than the old one, as expected.
That's all. Sorry for asking a question I could answer myself!!
But maybe it'll be useful to someone...