[ntp:questions] Cross-compiling NTP for the Raspberry Pi

David Taylor david-taylor at blueyonder.co.uk.invalid
Fri Feb 6 09:48:13 UTC 2015


On 06/02/2015 07:58, Brian Inglis wrote:
[]
> The VM approach below may be more straightforward for the kernel, and by
> adapting, for NTP:
> https://learn.adafruit.com/raspberry-pi-kernel-o-matic
> using VirtualBox and Vagrant.
> Note at the end there are links for different configs for different
> kernel distributions,
> other than Raspbian, and hints on adaptation.
>
> Also you may be able to xcompile using Windows Cygwin:
> https://www.google.ca/search?q=cygwin+arm+linux+toolchain
> especially:
> http://www.raspberrypi.org/forums/viewtopic.php?f=7&t=4058#p117498
> and followups.
> YMMV

Thanks, Brian.

Yes, the Adafruit approach is one I should look at, although now the 
kernel has PPS support built in the only thing I need to do there is 
push the Raspian team to support nohz=off, which seems to produce a 
noticeably lower jitter.  Many of the users I help find recompiling NTP 
difficult enough, without having to recompile and install a new kernel 
and modules as well.

With NTP, with the faster Raspberry Pi 2, compiling NTP is now less of 
an issue.  The configure step still takes a grossly long time and seems 
to have repeated tests for e.g. "what is the size of an integer", but 
the make step can now be run with -j5 to make it multi-task, and is much 
quicker.

What I have yet to discover is whether NTP compiled on the RPi 2 with 
its ARMv7 instructions will run correctly on the basic RPi with its 
ARMv6 instruction set.  Some say it will, but doesn't the compiler take 
advantage of the newer instructions?

I would recommend the RPi 2 to anyone developing software, though.  It's 
much faster.
-- 
Cheers,
David
Web: http://www.satsignal.eu



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