[PATCH u-boot-mvebu 00/31] kwboot / kwbimage improvements

[Marek Behún]

On Fri, 9 Jul 2021 14:35:15 +0200
Stefan Roese <sr at denx.de> wrote:

> Thanks. And could you please also do one (or more) boot-time
> comparisons, old vs. new version? This way we can see, if and how the
> boot-time is affected (perhaps improved, which would be great) by this
> patch series.

For Turris Omnia, the size of the u-boot-spl.kwb binary decreases by
~37 KiB, mainly due to not needing padding anymore. The size of the SPL
binary itself (u-boot-spl.bin) decreases by 7.5 KiB (due to code
reduction - no SPI NOR code).

Unfortunately the boot time increases by 815 ms, from 2341 ms (on
average) to 3156 ms (on average).
This is probably because BootROM read the memory differently (lower
frequency or some other reason).

I think this 815 ms increase in boot time into U-Boot prompt is worth
the 37 KiB saved space for U-Boot code (mainly because on Omnia we have
960 KiB for U-Boot and currently we are at 860 KiB, so enabling some
other features in the future may push us to the limit), but others may
not agree.

I am going to put this information also into v2 cover letter.

Marek