Re: NTP leap second question

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sep 15, 2005, at 02:49:21, Ulrich Windl wrote:
On 14 Sep 2005 at 11:54, john stultz wrote:
If I recall, leapsecond implementations are a pretty contentious issue. Some folks have suggested having the kernels note the leapsecond and slew the clock internally. This sounds nicer then just adding or

No! Never slew a leap second: It will take too long! It's all over after one second. If you slew, you time will be incorrect for an extended time.

I think he said "It's a contentious issue", and "Some have suggested". No need to get your underwear in a bunch over it. There are arguments for both sides. Besides, it's not like it matters much in the grand scheme of things, it's only a second. With the current proposals, the leap-second-slewing would only be in effect for 1000 seconds, and you'd never be very far off true time (The simplest implementation is one second off, if you add one bit of state you'll only ever be a half-second off). If you're willing to make it a bit slower and a bit more code, you could even make the slewing nonlinear with a continuous derivative, so it's only in place for ~20 seconds, and only changes rapidly near the leapsecond boundary itself. On the other hand, if your box is running a nuclear reactor, you might want to do a bit more verification, but Linux isn't certified for that anyways!! :-D

Cheers,
Kyle Moffett

--
Simple things should be simple and complex things should be possible
  -- Alan Kay



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]
  Powered by Linux