NAME

dis_cpu_time, dis_wall_time, seq_cpu_time, seq_walltime -- Time in seconds since an arbitrary time in the past.

SYNOPSIS

    double dis_cpu_time();


    double dis_wall_time();


    double seq_cpu_time();


    double seq_wall_time();

EXAMPLE

    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

DESCRIPTION

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 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.

seq_cpu_time is similar but returns the computing time per user for the current process. dis_cpu_time returns the accumulated CPU for all processed linked together via the default communicator.

COPYRIGHT

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.