John Cremona on Thu, 03 Nov 2022 17:26:20 +0100


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Re: timer output

Thanks, Andreas.  I had forgotten that parallelization happened silently behind the scenes!   I think there are 8 cores.

John

On Thu, 3 Nov 2022, 14:47 Andreas Enge, <andreas.enge@inria.fr> wrote:
Hello John,

Am Thu, Nov 03, 2022 at 02:32:29PM +0000 schrieb John Cremona:
> cpu time = 2,013 ms, real time = 421 ms.

two times are printed when you use the parallel version, recognisable
by a line such as
   threading engine: pthread
when starting GP.

Then "real time" is the wallclock time, and "cpu time" is the sum of the
CPU times spent by the different threads, the number of which is printed by
   default ("nbthreads")

I see this, for instance:
? isprime (nextprime (10^300))
cpu time = 3,220 ms, real time = 1,685 ms.
which reflects well that I have two cores (and four threads), and that
ECPP is well parallelised, apparently.

Andreas