[RFC PATCH u-boot 00/12] U-Boot LTO (Sandbox + ARM Nokia RX-51)

[Adam Ford]

On Fri, Mar 5, 2021 at 11:10 AM Adam Ford <aford173 at gmail.com> wrote:
>
> On Fri, Mar 5, 2021 at 6:31 AM Stefan Roese <sr at denx.de> wrote:
> >
> > On 05.03.21 12:25, Adam Ford wrote:
> > > On Thu, Mar 4, 2021 at 4:33 PM Marek Behun <marek.behun at nic.cz> wrote:
> > >>
> > >> On Thu, 4 Mar 2021 16:18:03 -0600
> > >> Adam Ford <aford173 at gmail.com> wrote:
> > >>
> > >>> diff --git a/arch/arm/mach-omap2/omap3/Makefile
> > >>> b/arch/arm/mach-omap2/omap3/Makefile
> > >>> index 91ed8ebc9f..a2cc21c6d2 100644
> > >>> --- a/arch/arm/mach-omap2/omap3/Makefile
> > >>> +++ b/arch/arm/mach-omap2/omap3/Makefile
> > >>> @@ -6,6 +6,8 @@
> > >>>   # If clock.c is compiled for Thumb2, then it fails on OMAP3530
> > >>>   CFLAGS_clock.o += -marm
> > >>>
> > >>> +CFLAGS_REMOVE_file.o := $(LTO_CFLAGS)
> > >>
> > >> Eh? There is no file.c in arch/arm/mach-omap2/omap3/ directory.
> > >
> > > It must be from something else that had changed when I did a git pull
> > > pull on your repo. I guess that's better news.
> >
> > It might be a misunderstanding. Marek means that you need to replace
> > "file" with your real filename, like:
> >
> > driver_spi.c ->
> >
> > +CFLAGS_REMOVE_driver_spi.o := $(LTO_CFLAGS)
>
> I first did a git pull from his git repo, and then blindly copy-pasted
> the suggested link to that above directly.  I don't play with
> Makefiles often, so I didn't really notice that I needed to match the
> line to an actual file.  When I rebuilt, my initial issue with showing
> too much DDR and hanging went away, so I wrongly assumed that this
> fixed it.  In reality, I think it was a patch that had been applied to
> his git repo that got pulled in at the same time.
>
> On the testing front,
> I started testing the da850evm (ARM9) this morning.  I ran into an
> issue that I apparently caused some time ago, and I'm trying to
> resolve that now.  I have it working, but I need to clean it up.  I'll
> push the clean-up to the ML then try the LTO on that board to see if
> U-Boot and/or SPL work with LTO enabled.
>
> As of now, I have one board that seems to fully boot (imx6q_logic) and
> a family of boards that work in U-Boot but not SPL (omap3_logic).
>
> After the da850em, I'll test a 64-bit Renesas board without SPL and a
> 64-bit NXP board with SPL to test.
>
> On the build-testing I have done, I am seeing an average of a 10-20%
> reduction in size for SPL, and a ~ 3% reduction in size in U-Boot.
>

With a patch that I've already sent to the mailing list for the
da850evm, it's booting both SPL and U-Boot

With the compiler I have, the code went from:
SPL        24305
U-Boot  381930

To:
SPL        20937
U-Boot  358780

For a Reduction of:
SPL    -3368 (-13.86%)
U-Boot -23150 (-6.06%)

I didn't test the NOR or NAND booting versions of the da850evm, but I
will try to do that when the time comes.

adam
> adam
> >
> > HTH,
> > Stefan