AM3351: Linux kernel boot time

Lukas Stockmann

Prodigy 80 points

Part Number: AM3351

Hi TI team,

as kernel 4.4. is EOL we have to update it and we'd like to go with 5.10.

But with kernel 5.10. boot time is doubled! e.g. customize_machine takes now ~3 sec.

I compared different kernel and SOC's, this effect is only on omap2, any idea??

This additional boot time is unacceptable for our factory!

Regards,

Lukas

am3351-boot-time.pdf

over 1 year ago

0 Bin Liu over 1 year ago

TI__Guru*** 125176 points

Hi Lukas,

I will take a look at the boot time for customize_machine() and get back to you.

What tool do you use to generate the nice boot time graph?

+1 Lukas Stockmann over 1 year ago in reply to Bin Liu

Prodigy 80 points

Hi Bin,

see page 26: opdenacker-timing-boot-time-reduction-techniques.pdf

FYI, we found a solution for customize_machine, [v2,00/17] Refactor fw_devlink to significantly improve boot time

Still open is the tracer_init_tracefs time.

Regards,

Lukas

0 Bin Liu over 1 year ago in reply to Lukas Stockmann

TI__Guru*** 125176 points

Hi Lukas,

Thanks for the tip. I use initcall_debug, but didn't know there is a tool to generate a graph from it.

Do you have the new time measurement of customize_machine() with the fw_devlink fixes?

tracer_init_tracefs() is part of the kernel tracing module. Should CONFIG_TRACING be disabled in your kernel release build in which the boot time matters?

0 Lukas Stockmann over 1 year ago in reply to Bin Liu

Prodigy 80 points

Yes, this is CONFIG_TRACING, but, why does it take longer now?

am3351-boot-time_2.pdf

0 Bin Liu over 1 year ago in reply to Lukas Stockmann

TI__Guru*** 125176 points

I am not sure, I only turn on kernel TRACING when I need to debug something.

You might want to debug into it to understand which sub routines takes more time in there.

0 Lukas Stockmann over 1 year ago in reply to Bin Liu

Prodigy 80 points

Hi Bin,

we will do some more debugging and plan b will be to turn off tracing.

Thanks,

Lukas

Processors

Processors forum

AM3351: Linux kernel boot time