[U-Boot] [PATCH 0/4] Accurate boot time measurement

Wolfgang Denk wd at denx.de
Mon May 16 13:18:22 CEST 2011


Dear Graeme Russ,

In message <BANLkTim55MVfJ-FdEkea3GSbvQnnaicASw at mail.gmail.com> you wrote:
>
> > time-stamping console output is not restricted to the serial port. It
> > works as well with tty over USB, or netconsole, or even netconsole
> > over USB.
> 
> My point is, if the device reboots in the field, you cannot recover the
> boot timing analysis as once it is streamed out it is gone forever

Agreed. But so far I have never seen a need to perform boot time
measurements on devices in the field without access to the console
(serial, or usb or netconsole).  In all my experience, such behaviour
is pretty much deterministic and can be done in the lab, before
shipping systems.

The only way where I can imagine that the boot ime depends on the
actual user environment is when booting from the network, but then
again you can also run a network sniffer to measure this impact.

I really wonder what the benefit of adding such code to U-Boot is.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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