DOKK / manpages / debian 11 / librheolef-dev / dis_cpu_time.7rheolef.en
dis_cpu_time(7rheolef) rheolef dis_cpu_time(7rheolef)

dis_cpu_time - cumulated cpu for distributed computations (rheolef-7.1)

double dis_cpu_time();
double dis_wall_time();
double seq_cpu_time();
double seq_wall_time();



    double t_start = dis_wall_time();


    ...stuff to be timed...


    double t_end   = dis_wall_time();


    derr << "That took " << t_end - t_start << " seconds" << endl


    double cpu_start = dis_cpu_time();


    ...stuff to be timed...


    double cpu_end   = dis_cpu_time();


    derr << "That needs " << cpu_end - cpu_start << " CPU seconds" << endl


See also diststream(2) for derr.

dis_cpu_time

Returns the accumulated CPU for all processed linked together via the default communicator.

seq_cpu_time

It is similar but returns the computing time per user for the current process only.

dis_wall_time

Returns a floating-point number of seconds, representing elapsed wall-clock time since some time in the past. The time in the past is guaranteed not to change during the life of the process. The user is responsible for converting large numbers of seconds to other units if they are preferred. This function is portable (it returns seconds, not ticks), it allows high resolution, and carries no unnecessary baggage. In a distributed environment, dis_wall_time clocks are synchronized: different nodes return the same time value at the same instant.

seq_wall_time

It is similar but the time returned is local to the node that called them and clocks are not synchronized: in a distributed environment, different nodes can return different local times, at different instant when the call to seq_wall_time is reached.

This documentation has been generated from file linalg/lib/dis_cpu_time.h

Pierre Saramito <Pierre.Saramito@imag.fr>

Copyright (C) 2000-2018 Pierre Saramito <Pierre.Saramito@imag.fr> GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

Sat Mar 13 2021 Version 7.1