A double has 53 bits in the mantissa which means that for a running time of about 24 hours you'd still have picoseconds. I doubt anyone cares about picoseconds when the running time is a day. That's why I think a Double is a good choice, it adapts to the time scale involved.
-- Lennart On Sun, Jan 11, 2009 at 4:03 PM, Peter Verswyvelen <bugf...@gmail.com> wrote: > wouldn't a double become less and less precise the longer the process is > running? > so Integer sounds like the only datatype that could work here... > and why not do it like in Windows: make two functions, one that returns the > number of CPU ticks, and another that returns the frequency (number of ticks > per second)... This gives you an API that works for whatever clock speed... > > > > On Sun, Jan 11, 2009 at 11:23 AM, Lennart Augustsson > <lenn...@augustsson.net> wrote: >> >> It was suggested that it should be ns, and I complained that ns would >> be obsolete in a while. >> What I really wanted was a switch to Double (and just using seconds), >> instead we got ps. >> At least ps won't get obsolete in a while. >> >> -- Lennart >> >> On Sun, Jan 11, 2009 at 12:06 AM, ChrisK <hask...@list.mightyreason.com> >> wrote: >> > Manlio Perillo wrote: >> >> >> >> Hi. >> >> >> >> Just out of curiosity, but why Haskell 98 System.CPUTime library module >> >> uses picoseconds instead of, say, nanoseconds? >> >> >> >> At least on POSIX systems, picoseconds precision is *never* specified. >> >> >> > >> > I have not idea. But at a guess, I would say that 1 ns is not such a >> > small >> > time interval anymore. The CPU speeds are about 3 GHz, so 0.3 ns per >> > CPU >> > clock. Even the RAM clock in a laptop (e.g. Apple's 17" Mac Pro) is 1066 >> > MHz, so the internal there is just under 1 ns. >> > >> > Whoever picked picoseconds has made it possible to talk about a single >> > clock >> > interval for hardware like this. >> > >> > -- >> > Chris >> > >> > _______________________________________________ >> > Haskell-Cafe mailing list >> > Haskell-Cafe@haskell.org >> > http://www.haskell.org/mailman/listinfo/haskell-cafe >> > >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe@haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe > > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe