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Google's New Public NTP Servers Provide Smeared Time (googleblog.com)

Posted by msmash on from the fixing-things dept.

Google says it has built support for the leap second into the time servers that regulate all Google services. An anonymous reader shares a blogpost by Google:No commonly used operating system is able to handle a minute with 61 seconds, and trying to special-case the leap second has caused many problems in the past. Instead of adding a single extra second to the end of the day, we'll run the clocks 0.0014% slower across the ten hours before and ten hours after the leap second, and "smear" the extra second across these twenty hours. For timekeeping purposes, December 31 will seem like any other day. All Google services, including all APIs, will be synchronized on smeared time, as described above. You'll also get smeared time for virtual machines on Compute Engine if you follow our recommended settings. You can use non-Google NTP servers if you don't want your instances to use the leap smear, but don't mix smearing and non-smearing time servers.

11 of 179 comments (clear)

  1. Re:Does this mean.... by Anonymous Coward · · Score: 5, Funny

    Does this mean that my DPS will be slightly higher on December 31st?

    No. It means you'll lose a second of uptime.

  2. Not new, just a holiday reminder PSA by Anonymous Coward · · Score: 5, Informative

    Google has been smearing leap seconds over NTP since 2011. This is a public reminder that Google NTP will be serving smear seconds because there is one coming.

  3. Sounds like a part of the Star Trek:DTI Manual by wiredog · · Score: 5, Funny

    "don't mix smearing and non-smearing time servers"

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    Best Slashdot Co
  4. Some examples of smeared time by squiggleslash · · Score: 5, Funny

    At 4.37 it'll report that 4.38 molests goats. 4.38 will retaliate by claiming 4.37 killed a man and lied about it. 4.39 will accuse 4.38 of secretly having two wives who know nothing about one another. 4.40 will claim 4.38 and 4.37 are having a secret affair and are making up allegations about one another to hide the fact. 4.41 will claim 4.40 is a multiple felon. 4.42 will accuse 4.41 of cheating on his taxes...

    --
    You are not alone. This is not normal. None of this is normal.
    1. Re:Some examples of smeared time by Ashtead · · Score: 4, Funny

      And meanwhile 4:20 enjoys a joint off to the side.

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      SIGBUS @ NO-07.308
  5. Re:Falsehoods Developers Believe About Time by heypete · · Score: 4, Informative

    Because that's how they did it before and they consider it "safer" in the context of not making uneccessary changes this soon to the leap second. In the future they plan to do it 24 hours in advance:

    Although we decided it would be safest for Google's infrastructure to handle the 2016 leap second using a 20-hour smear, the same way we handled the leap seconds in 2012 and 2015, this is not the only smear that works well. Many organizations use smeared clocks, and it would be helpful if the smears were the same. After all, the purpose of clocks is to read the same time in different places.

    We would like to propose to the community, as the best practice for leap seconds in the future, a 24-hour linear smear from noon to noon UTC. We plan to use this smear starting from leap second #38, which is likely to be in 2018.

    Source: https://developers.google.com/time/smear.

  6. Well actually... by watermark · · Score: 4, Funny

    *pushes glasses up* *straightens pocket protector*

    Actually, they would need to run the clocks 0.0013889% slower. If ran the clocks 0.0014% percent slower, they would gain 1.008 seconds instead of just 1 second even.

    Hire me Google. I'll save the internets for you.

  7. Tired of this shit. by LTIfox · · Score: 5, Interesting

    Can we just move to TAI and convert to UTC only when interfacing the meatspace?

  8. Re:O cursÃd spite by Bruce+Perens · · Score: 4, Funny

    Geez, foiled by Slashdot's non-UTF8-ness again.

    --
    Bruce Perens.
  9. Re:Hey look the flow rate is a little high. by MightyYar · · Score: 4, Insightful

    Just make the stocks trade in time-coordinated batches. The batches can still be relatively fast - even every second - just so it is slow enough to stop the stupid games with the speed of communications.

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    W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
  10. Re:It's not that easy by Xylantiel · · Score: 4, Insightful

    It's funny to me that they say the Earth's rotation is "determined" by IERS. No, it is *measured*. A subtle implied difference, but a critical one. The problem here is actually with unix time, not UTC. TAI as an alternative to unix time actually makes pretty decent sense. When was the last time you manually converted from seconds since epoch to day/month/year?

    I think the point is that since time zones are actually updated more frequently for political purposes than leap seconds occur, it makes sense, for network-connected computers at least, to just stuff the leap seconds in the same distribution channels (already done actually) and abandon trying to hack around the clumsy (non-monotonically increasing) definition of unix time.