[Haskell-cafe] erratic behavior for System.Time.diffClockTimes

[Antoine Latter]

On Fri, Apr 8, 2011 at 3:48 PM, Warren Harris <warrensomebody at gmail.com> wrote:
> I'm trying out GHC-7.0.3-x86_64 for Mac OS X and see what seems to be a bug in System.Time.diffClockTimes. The TimeDiff tdPicosec field returns values that seem to jump around erratically:
>
> test = do
>  startTime <- System.Time.getClockTime
>  endTime <- System.Time.getClockTime
>  let dt = diffClockTimes endTime startTime
>  putStrLn $ show dt
>
> Prelude Test> test
> TimeDiff {tdYear = 0, tdMonth = 0, tdDay = 0, tdHour = 0, tdMin = 0, tdSec = 0, tdPicosec = 0}
> Prelude Test> test
> TimeDiff {tdYear = 0, tdMonth = 0, tdDay = 0, tdHour = 0, tdMin = 0, tdSec = 0, tdPicosec = 3000000}
> Prelude Test> test
> TimeDiff {tdYear = 0, tdMonth = 0, tdDay = 0, tdHour = 0, tdMin = 0, tdSec = 0, tdPicosec = -3329012246138323150000000}
> Prelude Test> test
> TimeDiff {tdYear = 0, tdMonth = 0, tdDay = 0, tdHour = 0, tdMin = 0, tdSec = 0, tdPicosec = 3000000}
> Prelude Test> test
> TimeDiff {tdYear = 0, tdMonth = 0, tdDay = 0, tdHour = 0, tdMin = 0, tdSec = 0, tdPicosec = -3329012246138322851000000}
> Prelude Test>
>

There's already a ticket:

http://hackage.haskell.org/trac/ghc/ticket/4970

It is specific to 64bit on Mac OS. I noticed it myself a bit ago.
Please add yourself to the CC list on the ticket if its affecting you.

Antoine