[LEAPSECS] happy anniversary pips

[Warner Losh]

On Feb 12, 2014, at 1:50 PM, Harlan Stenn wrote:

> The conclusions I draw from the utter lack of any similar reports from

> non-linux systems are:

> 

> - either those kernels/libraries did not do leap-second processing, or

> - they did and their code worked

> 

> Do you have different conclusions?


Yes.

Linux is more popular and examined than other systems. Linux is more open than Windows, so bugs there won't be as well publicized. Linux is more popular than FreeBSD, which also handles leap seconds in the kernel. There have been about half a dozen bugs in FreeBSD's leap second handling that I've fixed over the years. The code mostly works, but I'm sure if it were studied in detail some aspect of leap seconds wouldn't be handled pedantically correctly (absolute timeouts for condvars in posix will, for sure, take a second longer to timeout across a leap second boundary).

Linux is also has a higher rate of change and rewrite than FreeBSD, which is another reason it gets tripped up by these issues more often. The number of extant linux kernel versions is quite large compared to most other systems as well. With this much change, there's sure to be something overlooked, and quite often it is the "edge" cases, like leap seconds.

Other systems are less open, and sweep this data under the rug is also a valid conclusion.

Warner