On 03/02/2020 13:11, Stephen Jones wrote:
>
> The connection with scaling comes from what Jeff mentioned. Wallclock
> time is ordinarily understood to be the time you would get with a stop
> watch if you actually stood there and timed the job. But the scheme
> used to make a heterogeneous cluster appear to be a homogeneous
> cluster requires that the times are scaled, and hence are not the time
> you would get with a stop watch; which is confusing to say the least.
> With respect to the other point: efficiency: if both times are scaled
> by the same factor, you can use the same equation to yield efficiency,
> i.e. efficiency = cputime/wallclocktime.
PS: It's not that wallclocktime/cputime can be conflated ....they are
different things as you say.
The first point is that wallclocktime is useful on its own for a site to
see who has been using the nodes, while cputime can only be useful in
conjunction with wallclocktime to get efficiency. And the second point
is that efficiency, the only reason to care about cputime, can still be
obtained in the exact same way from scaled data.
Cheers,
Ste
--
Steve Jones [log in to unmask]
Grid System Administrator office: 220
High Energy Physics Division tel (int): 43396
Oliver Lodge Laboratory tel (ext): +44 (0)151 794 3396
University of Liverpool http://www.liv.ac.uk/physics/hep/
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