[U-Boot] During boot is U-Boot doing its jobs sequentially or in parallel?

[Frank Ihle]

Hello again,

I recently wrote an E-Mail about silenting the output during the U-Boot sequence, but I thougt it's better to open up a new thread. BTW this is not a problem, I just want to know.

I realized a behavior of U-Boot, which isn't quiet clear to me. I have an ARM9 SAM9G25, that has this boot sequence: AT91Bootstrap -> U-Boot 2010.06 -> Linux 2.6.39. With that system I did 4 Test series about silencing the U-Boot output:

- An image with U-Boot output, without network support in U-Boot - takes about 10.6 s to boot.
- An image like above, but without U-Boot output - takes about 10.4 s to boot.
--> 200 ms gained

- An image with U-Boot output, with network support in U-Boot- takes 12.30 s
- An image without U-Boot output, but with network support in U-Boot takes 12.30 s too.
--> 0 ms gained

Now why is it, when I disable the output, the time stays the same with network support, but around 200 ms are saved without the network? One thing that comes to my mind U-Boot doing its jobs in parallel, is that true? Since there's a waiting when initializing the network there's enough time to do the output ?

Kind Regards

Frank