Martin Burnicki wrote: > The driver package provides an API call which reads both the time from > the card and the current system time as close as possible after each > other, and these timestamp pairs can be fed into ntpd via ntpd's SHM > driver, thus yielding hery good accuracy.
BTW, here is a loopstats graph from a system running openSUSE Tumbleweed with Linux kernel 4.3.3 and ntpd 4.2.8p4: https://www.meinberg.de/download/loopstats-linux-4.3.3-ntpd-4.2.8p4-gps180pex.pdf The reference clock is a Meinberg GPS180PEX PCI Express card: https://www.meinbergglobal.com/english/products/pci-express-gps-clock.htm Please keep in mind that the mean accuracy also depends strongly on the stability of the Quartz oscillator on the PC mainboard, i.e. how much its frequency varies due to variations of the ambient temperature, inside and outside the PC's housing. Also some other attributes like CPU type, chipset on the mainboard etc. may affect the performance of time synchronization. Martin -- Martin Burnicki Senior Software Engineer MEINBERG Funkuhren GmbH & Co. KG Email: [email protected] Phone: +49 (0)5281 9309-14 Fax: +49 (0)5281 9309-30 Lange Wand 9, 31812 Bad Pyrmont, Germany Amtsgericht Hannover 17HRA 100322 Geschäftsführer/Managing Directors: Günter Meinberg, Werner Meinberg, Andre Hartmann, Heiko Gerstung Web: http://www.meinberg.de _______________________________________________ pool mailing list [email protected] http://lists.ntp.org/listinfo/pool
