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 running. -----Original Message----- From: "David J Taylor" <[email protected]> Sender: [email protected] Date: Thu, 25 Oct 2012 06:03:44 To: Time-Nuts<[email protected]> Reply-To: Discussion of precise time and frequency measurement <[email protected]> Subject: Re: [time-nuts] Timing performance of servers
Fellow time-nuts, When spending time on a conference last week, I heard one interesting comment that they lost data due to bad timing on their Windows servers. [] If you need better performance than that, you should use NTP (and then download and install Meinbergs Windows-client for NTP). Then again, I would point out that for this type of data, it would most probably be better served on a Linux box. What should be a nice wake-up call for them would be a summation of how different strategies would give them clock precision of sufficient grade. So, does anyone know of such measurements presented anywhere? [] Cheers, Magnus ==================================================== Magnus, If it helps, I have my own measurements of the Meinberg NTP port and later versions running on Windows here: http://www.satsignal.eu/mrtg/performance_ntp.php Strategy: 1 - have one FreeBSD (not Linux) server, although this is now not essential, but it's nice as a confirmation that the rest is working OK. 2 - Configure some Windows PCs as stratum-1 servers fed from GPS. On the plots above, PCs Alta, Bacchus, Feenix and Stamsund are acting as stratum-1 servers. These all have serial port connections, and cover the OS range Windows 2000, XP, Win-7/32 and Win-7/64. All are using the kernel-mode serial port driver patch developed by Dave Hart. PC Pixie is the FreeBSD box. 3 - For the client PCs, use a fixed 32-second polling interval to the local stratum-1 servers, with Internet servers as a backup polled at 1024 seconds, resulting in a configuration file something like: _______________________________________________ # Use drift file driftfile "C:\Tools\NTP\etc\ntp.drift" # Use specific local NTP servers server 192.168.0.3 iburst minpoll 5 maxpoll 5 prefer # Pixie server 192.168.0.2 iburst minpoll 5 maxpoll 5 # Feenix server 192.168.0.7 iburst minpoll 5 maxpoll 5 # Stamsund # Use pool NTP servers pool uk.pool.ntp.org iburst minpoll 10 _______________________________________________ The client performance varies, with some of the best results being on a Windows-8 Wi-Fi connected PC which seems to have very good drivers (PC Bergen). Jitter is 40 - 110 microseconds. Windows XP also shows low jitter, but greater offset (within 250 microseconds). Windows Vista was the worst performer I had, but that PC has now been retired. There are discussions in progress at the moment about improving Windows-Vista and Windows-7 as a Windows time interval setting and reporting bug has been discovered, particularly affecting NTP. Cheers, David -- SatSignal Software - Quality software written to your requirements Web: http://www.satsignal.eu Email: [email protected] _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
