On 09/04/2013 04:04 PM, H. Peter Anvin wrote: > On 09/04/2013 03:59 PM, John Stultz wrote: >> Also, there's been talk of a slewed-leap-second clockid, basically UTC >> but around the leapsecond it slows down to absorb the extra second. This >> means that clockid would have a subsecond offset from TAI. >> > Most of what I have heard seem to center around abolishing leap seconds > entirely. Now, I know that some users do slewed leap seconds as a > unofficial policy to avoid rare events. Well, Google does their own slewed leap-seconds internally (using a modified ntp server to slow CLOCK_REALTIME on clients), and I believe AIX also provides similar behavior w/ their CLOCK_REALTIME clockid (they also provide CLOCK_UTC for those who have the need for UTC/leapseconds). And there's also some occasional talk of trying to standardizing a leap-second free UTC.
I suspect we have to have an all-of-the-above policy with the kernel. So we now (as of 3.10) support CLOCK_TAI, as well as the UTC-based CLOCK_REALTIME. If we can get some agreement on what the slewed-leapsecond adjustment should look like (have to decide what the slewing rate/range is: do we absorb the second over the last-hour, half-hour, 15-minutes before and after?), then we can add such a clockid (CLOCK_UTC_SLS?) to the kernel as well. thanks -john -- 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/
