[time-nuts] Timing performance of servers

David J Taylor david-taylor at blueyonder.co.uk
Thu Oct 25 02:16:52 EDT 2012

-----Original Message----- 
From: lists at lazygranch.com
Just a FYI here, using Dave's logging program, I found large errors in NTP 
when the antivirus did its thing. I don't know if it was due to CPU activity 
interfering with NTP or the cabinet heating up when the antivirus was 

Take a look at the plots for Bacchus:


There is a disk optimiser which kicks in on Wednesday at 03:00 UTC, and the 
box goes to 100% CPU for an hour.  The offset reported by NTP goes from 0 to 
about +1 millisecond, and recovers over the next 150 minutes or so after the 
CPU use goes back to its near-zero resting level.

With the PCs as stratum-1 servers, ambient or usage induced temperature 
variations do appear to be the main source of error, but not with Windows-7 
client PCs served over the LAN.

SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 

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