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Comment by geofft | Hacker News Reader

This looks like a paper about the Huygens system, with comparison to other protocols like PTP: https://www.usenix.org/system/files/conference/nsdi18/nsdi18...

Also these slides: https://platformlab.stanford.edu/Seminar%20Talks/retreat-201...

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I maintain an NTP implementation. That comparison doesn't seem fair to me. It looks like they are comparing the old reference NTP implementation and not really the protocol itself. An NTP implementation can certainly synchronize clocks with better accuracy than 1 millisecond, or even 1 microsecond with hardware timestamping and good network switches.

There are some interesting ideas in the Huygens paper, but I don't see anything that couldn't be done also with NTP.

The other thing I don't understand is that this paper argues against hardware timestamping on the grounds that users won't want to buy expensive hardware, and that Huygens is for "standard hardware ... in current data centers". Expensive, niche hardware is normal for the HFT folks that care about nanosecond precision.

The paper did not have hft as its primary use case, but you cannot contain reporters tendency to cherry pick eye catching aspects.

Yes, it seems that the designers tried to make something that would work in the current Google data centers. Which is not surprising as some of the authors work at Google.

I'd more want to know: why does Google need even better synchronization of time stamps than what they have now?

Good support for PTP in network switches is rare. If the users don't want to spend a lot of money on new switches with PTP support, they can synchronize clocks in the network with a protocol which doesn't require special support in switches.

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