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

[Adam Ford]

On Thu, Mar 4, 2021 at 8:58 AM Tom Rini <trini at konsulko.com> wrote:
>
> On Thu, Mar 04, 2021 at 07:46:18AM -0600, Adam Ford wrote:
> > On Thu, Mar 4, 2021 at 4:43 AM Marek Behun <marek.behun at nic.cz> wrote:
> > >
> > > On Wed, 3 Mar 2021 16:36:05 -0500
> > > Tom Rini <trini at konsulko.com> wrote:
> > >
> > > > So, as I start testing things locally with two additional changes (1.
> > > > LTO by default 2. No ffunction/data-sections with LTO) we see:
> > > > https://gist.github.com/trini/350ab850c42293563228b8d68a1bb89a
> > > > as the detailed size reduction.  This also shows that with LTO we want
> > > > to turn off -ffunction-sections/etc as it's not useful now.
> > >
> > > Tom, I have pushed another version to github PR to trigger CI, and am
> > > still working on clang. You can look at the github PR if you want to
> > > try yourself. I have also added patch that disables
> > > -ffunction-section/fdata-section on arm.
> > >
> > > After I manage to make it all work in CI I will send v2 to mailing list.
> >
> > I tested this with the imx6q_logic board.  I only tested the U-Boot
> > portion, but it appeared to work and it booted the kernel.  The U-Boot
> > size reduced -7182 bytes (about 3% smaller).
> >
> > I haven't been able to successfully boot the OMAP3 boards I have yet.
> > I'm still looking into this.
>
> It boots (and pytest runs) on my Beagleboard xM, fwiw.

Interesting.  with LTO enabled, the DRAM reports 7.2 GB and hangs.
Without LTO, U-Boot boots fine.

LTO:
OMAP3630/3730-GP ES1.2, CPU-OPP2, L3-200MHz, Max CPU Clock 1 GHz
Model: LogicPD Zoom DM3730 Torpedo + Wireless Development Kit
Logic DM37x/OMAP35x reference board + LPDDR/NAND
DRAM:  7.2 GiB
<hang>

Without LTO:
OMAP3630/3730-GP ES1.2, CPU-OPP2, L3-200MHz, Max CPU Clock 1 GHz
Model: LogicPD Zoom DM3730 Torpedo + Wireless Development Kit
Logic DM37x/OMAP35x reference board + LPDDR/NAND
DRAM:  256 MiB
NAND:  512 MiB
MMC:   OMAP SD/MMC: 0
Loading Environment from NAND... OK
OMAP die ID: 619e00029ff800000168300f1502501f
Net:   smc911x-0
Hit any key to stop autoboot:  0
OMAP Logic #

adam
>
> --
> Tom