3 ms·
> But given that NTP (either ntpd or chrony) tends to give me an estimated error of around (tens of) 1e-6 seconds, and PTP can get down to 1e-9 seconds, I'm not
by stingraycharles 4y ago
> But given that NTP (either ntpd or chrony) tends to give me an estimated error of around (tens of) 1e-6 seconds, and PTP can get down to 1e-9 seconds, I'm not sure how many data centre applications need that level of accuracy.
I know that in trading, auditing trades / order books requires extremely accurate timing, and they typically deploy GPS hardware to get the required level of accuracy. As GPS is accurate to a level of 30ns, 1e-6 to 1e-9 (1ns) is exactly the kind of improvement needed to not need GPS hardware anymore.
- throw0101a 4y ago> […] improvement needed to not need GPS hardware anymore. You're simply trading NTP hardware for PTP hardware (grandmaster clocks). There is no way to get to 1e-9 scales without hardware support.
- bradknowles 4y agoThese days, all the vendors I know of are shipping hardware that does both. So, it's not just an NTP server, it's also a PTP server. Maybe you don't use one or the other part of that functionality, or maybe they are licensed separately, but they are there.
- bradknowles 4y agoA good Stratum-1 GNSS from a company like Meinberg or Microchip will include a Rubidium or Cesium reference clock that is then disciplined by GPS and can get you down to sub-nanosecond level accuracy.