[ntp:questions] Nice fanless high-perf NTP server: Fitlet!

Paul tik-tok at bodosom.net
Fri Jan 16 16:23:44 UTC 2015


On Fri, Jan 16, 2015 at 2:02 AM, Terje Mathisen <terje.mathisen at tmsw.no>
wrote:

>
> Anyway it is definitely possible to get into the 100K to 1M
> requests/second range.
>
> As I noted above the real problem isn't in the actual packet processing,
> which can be made very efficient indeed for the normal case of client mode
> request/reply, but in all the HW/driver/OS overhead that's occured before
> you get those packets in&out of the ntpd process.
>
> Re. the Fitlet: With a 3.9 to 4.5 W power budget this box will never get
> into those ranges, but even handling 1K requests/second with sub-ms jitter
> and delay would still be a very nice Pool server.
>

On Fri, Jan 16, 2015 at 5:22 AM, Hal Murray <hmurray at megapathdsl.net> wrote:

> A Raspberry PI can do 1500 packets per second.
>

M Tharp's Laureline <
https://www.tindie.com/products/gxti/laureline-gps-ntp-server> can responds
to thousands of requests per second using an Arm Cortex processor.  The
trick is doing the right thing.  His code is efficient and there's no OS.
Just a framework to hang some drivers on, a PHY interface and a GPS.  It
could probably be considered the appliance instantiation of ntimed-master.
It's too bad he stopped making them.  Mine has typically has O(10)
microseconds of offset/jitter from other clique members as you'd expect
from 100Mb ethernet.

There are various NTPd things it doesn't do; some folks would consider that
a win.


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