On Wed, 28 Dec 2005, Arjan van de Ven wrote:
>
> yup that's why the patch only does it for gcc4, in which the inlining
> heuristics finally got rewritten to something that seems to resemble
> sanity...
Is that actually true of all gcc4 versions? I seem to remember gcc-4.0
being a real stinker.
> > Also, the inlining patch apparently makes code larger in some cases,
> > so it's not even a unconditional win.
>
> .... as long as you give the inlining algorithm enough information.
> -fno-unit-at-a-time prevents gcc from having the information, and the
> decisions it makes are then less optimal...
>
> (unit-at-a-time allows gcc to look at the entire .c file, eg things like
> number of callers etc etc, disabling that tells gcc to do the .c file as
> single pass top-to-bottom only)
I'd still prefer to see numbers with -funit-at-a-time only. I think it's
an independent knob, and I'd be much less worried about that, because we
do know that unit-at-a-time has been enabled on x86-64 for a long time
("forever"). So that's less of a change, I feel.
Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
