[U-Boot] [PATCH 2/2] board: tbs2910: Remove FIT support in defconfig to reduce u-boot size

Fri Jan 11 06:27:52 UTC 2019

On Thu, Jan 10, 2019 at 11:47 PM Stefano Babic <sbabic at denx.de> wrote:
>
> Hi Tom,
>
> On 10/01/19 16:12, Tom Rini wrote:
> > On Thu, Jan 10, 2019 at 03:51:51PM +0100, Stefano Babic wrote:
> >> Hi Tom,
> >>
> >> On 10/01/19 15:44, Tom Rini wrote:
> >>> On Thu, Jan 10, 2019 at 09:00:13AM +0100, Stefano Babic wrote:
> >>>> Hi Tom, Soeren,
> >>>>
> >>>> On 09/01/19 23:39, Tom Rini wrote:
> >>>>> On Wed, Jan 09, 2019 at 05:01:37PM +0100, Stefano Babic wrote:
> >>>>>> Hi Soeren,
> >>>>>>
> >>>>>> On 08/01/19 12:03, Soeren Moch wrote:
> >>>>>>> Hi Stefano,
> >>>>>>>
> >>>>>>> On 08.01.19 11:24, Stefano Babic wrote:
> >>>>>>>> Hi Soeren,
> >>>>>>>>
> >>>>>>>> On 08/01/19 11:14, Soeren Moch wrote:
> >>>>>>>>> Stefano,
> >>>>>>>>>
> >>>>>>>>> can you apply this for v2019.01? This is really a important fix to avoid
> >>>>>>>>>  environment and u-boot binary overwriting each other.
> >>>>>>>>> It is also a small local fix which cannot hurt anybody else.
> >>>>>>>> I will apply and I send a new PR. This is not the first fix in this
> >>>>>>>> direction, u-boot becomes pretty large, it is becoming a common problem.
> >>>>>>>>
> >>>>>>> Thank you very much.
> >>>>>>>
> >>>>>>> Yes, "in the good old days (tm)" there was much effort put into not
> >>>>>>> increasing the binary size for existing boards when adding new features.
> >>>>>>
> >>>>>> Right, fully agree.
> >>>>>>
> >>>>>>> Unfortunately this is not true anymore.
> >>>>>>
> >>>>>> I get in the same trouble with more as one project. A previous rule of
> >>>>>> thumb was to reserve 512KB to the bootloader because it was pretty
> >>>>>> unthinkable that bootloader could be larger. Mhmmhh....this remember me
> >>>>>> someone else who said that 640Kb is enough for everything.
> >>>>>>
> >>>>>> Anyway, as you noted, this is a big problem in field and it makes
> >>>>>> difficult an upgrade without returning back the device to factory, what
> >>>>>> nobody wants.
> >>>>>
> >>>>> So, this is more on me, so I should probably explain a little, and point
> >>>>> at the biggest culprit too.  The biggest at times culprit and sometimes
> >>>>> controversial thing is that we default to the EFI subsystem being on by
> >>>>> default.  This is 50KiB on tbs2910.
> >>>>
> >>>> I am not sure if we should point to EFI as responsible for the increased
> >>>> footprint or it is due to the sum of several components / factors. I
> >>>> just report my experience in last month : I had to port U-Boot for a
> >>>> customer from a not very old release (2017.01) to the current. 2017.01
> >>>> had already (apart of FIT support) all features the customer needed, but
> >>>> there are issues(NAND, UBI) and I kew that they were solved later.
> >>>> Processor was an old PowerPC 8308, a quite dead SOC. I have not changed
> >>>> a lot in board code, but of course I had to reconfigure a lot. At the
> >>>> end, everything worked but I was quite astonished about footprint. I had:
> >>>>
> >>>> 2017.01    u-boot.bin 443452
> >>>> 2018.11 u-boot.bin 654684
> >>>> I'm splitting my reply here into two emails.  This here concerns the
> >>> heck out of me.  But I don't see it on MPC8308RDB.  There I see:
> >>>    powerpc: (for 1/1 boards) all -124241.0 bss -131040.0 data -48.0 text +6847.0
> >>>             MPC8308RDB     : all -124241 bss -131040 data -48 text +6847
> >>>                u-boot: add: 108/-85, grow: 121/-49 bytes: 22672/-148318 (-125646)
> >>
> >> Maybe I confuse you - this is a custom board, similar to MPC8308RDB, but
> >> it is not MPC8308RDB. But nevertheless, I could not understand the
> >> difference is sitze.
> >
> > Right, I understand, that's just the first MPC83xx board I spotted, and
> > I wanted to see if all platforms had such unreasonable growth.  You're
> > showing your custom platform went up by _200_ kilobytes.
>
> I have found that one of the major reason is the different toolchain.
> 2018.11 was built with the toolchain requested by customer, it was gcc
> 6.4. I built 2017.01 with buildman and fetching the toolchain, that
> means 7.3. The same U-Boot versione produces very different footprint,
> much better with the newer toolchain. At least 50-60KB are due to the
> toolchain. LibFDT + FIT image (new features I added) produces ~70Kb more
> code. But then, yes, I want to have them. So at the end, one big
> responsible is the toolchain. So partially I am responsible for new
> footprint (new features), the rest is done by toolchain.

That looked promising, so I gave it a try as well: I'm normally using gcc 6.3
from Debian 9. Comparing the sizes of this and buildman-provided 7.3, I
got a reduction of 100-200 Bytes only (both for SPL and U-Boot) with 7.3.

So your 50 KiB reduction must have been a corner case I guess...

Regards,
Simon

>
>
> >
> >>> And in terms of .bins:
> >>> -rwxrwxr-x 1 trini trini 337400 Jan 10 09:37 /tmp/MPC8308RDB/new/01_of_11922_g80d261881f93ee474d1c9188b5c2b5b42b0c4e6f_powerpc--T2080QDS--R/MPC8308RDB/u-boot.bin
> >>> -rwxrwxr-x 1 trini trini 345804 Jan 10 09:37 /tmp/MPC8308RDB/new/11922_of_11922_g0157013f4a4945bbdb70bb4d98d680e0845fd784_Prepare-v2018.11/MPC8308RDB/u-boot.bin
> >>>
> >>> I am doing all of mpc83xx now to see if something else trips such a
> >>> large growth.
> >>>
> >>
> >> I will do the same here on this board and try to understand where the
> >> difference is coming from. I will report to you, then.
> >
> > Thanks!
> >
>
> Regards,
> Stefano