[ntp:questions] Have Pi, have GPS = low powered NTP server?

pktrigg at gmail.com pktrigg at gmail.com
Sun Aug 26 06:11:33 UTC 2012


On Sunday, August 26, 2012 2:40:27 AM UTC+8, Chris Albertson wrote:
> On Sat, Aug 25, 2012 at 10:39 AM, John Hasler <jhasler at newsguy.com> wrote:
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> 
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> > pktrigg writes:
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> > > I have my pi running on the web right now at http://121.221.94.250/
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> 
> 
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> Not the fastest server on the 'net but I was able to see the page
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> (eventually)
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> One trick for slow servers or slow links is to make the main page VERY tiny
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> with just a small amount of plain text and links to the pages with
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> graphics, tables and the like.
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> -- 
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> 
> 
> Chris Albertson
> 
> Redondo Beach, California

Hi Chris,
my suburb has a 50yo 'rim' for phone and ADSL1, which services hundreds of homes from a single copper pair.  3G does not work as we are in a shadow of a hill.  This means I am shaped upload to 115k bits/sec.  I agree the page needs to be smaller if this were permanent, but the root cause is terrible infrastructure in my area.
I was hoping to make the page really easy to use, so folks can better understand what ntp is all about, and what is going on when it goes wrong.

I should have a gps soonish, but I am pretty happy so far (only had my pi for 3 nights)
The plot in the web page is starting to reveal some spikes int he clock offset.  I need to investigate these some more, as they really should not exist.  The plot comes from a decode of the loopstats file.

I will leave it running for a few days and see how it settles, but I suspect the spikes are real.  My concern is the spikes are in the raspi hardware interrupts, not the ref clock or ntp.  

Time will tell.




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