[time-nuts] Comparing the BeagleBone Black & Raspberry Pi as NTP servers

Attila Kinali attila at kinali.ch
Sun Mar 22 08:58:43 EDT 2015

On Sat, 21 Mar 2015 16:23:30 -0000
"David J Taylor" <david-taylor at blueyonder.co.uk> wrote:

> I've just put up my first draft of a comparison of these two popular devices 
> as NTP servers:
>   http://www.satsignal.eu/ntp/BBB-vs-RPi.html
> Comments welcomed - I know it's an imperfect test!

Something is wrong here. I would expect the BBB to perform at least
as well as the rpi (after all, the BBB has an ethernet MAC with
IEEE1588 support, while the rpi is basically a glorified USB controller
with attached graphics card).

You are most likely running services on the BBB (network services,
local services, cron jobs,...) that cause the high, and spikey
cpu load, which in turn destroys your ntp performance.

Also, compare your results to [1], where Dan Drown uses the
capture/compare unit of the AM3359 to timestamp the PPS and use
this for ntp. In [2] he tries to measure the temperature dependence
of the BBB oscillator (not be best way, but...).

			Attila Kinali

[1] http://blog.dan.drown.org/beaglebone-black-timer-capture-driver/
[2] http://blog.dan.drown.org/tcxo-beaglebone-black/

< _av500_> phd is easy
< _av500_> getting dsl is hard

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