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

[Adam Ford]

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.

adam
>
> HTH,
> Stefan