[Haskell-cafe] Re: System.CPUTime and picoseconds

Lennart Augustsson lennart at augustsson.net
Sun Jan 11 05:23:58 EST 2009

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 <haskell at 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
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