[gmx-developers] Timing

[Roland Schulz]

Hi,

Is there a good reason to summing the time on all cores, when print the
timing (function wallcycle_sum)? In case there is a load imbalance the
maximum norm (multiplied with the number of cores) gives a much more
reasonable time, because the other cores will wait adding practially to the
time. In case their is no load imbalance changing the norm gives the same
result.

I noticed that in the case where a significant amount of time is spent in
write_traj. Then the printed time is still very small, because only one core
(rank=0) is spending time so that the sum is not much affected (for many
cores).

BTW: what is GMX_CYCLE_ALL doing?

Roland





-- 
ORNL/UT Center for Molecular Biophysics cmb.ornl.gov
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