.TH "dis_cpu_time" 7rheolef "Sat Mar 13 2021" "Version 7.1" "rheolef" \" -*- nroff -*-
.ad l
.nh
.SH NAME
dis_cpu_time \- cumulated cpu for distributed computations (rheolef-7\&.1)
.SH "SYNOPSIS"
.PP
.PP
.nf
double dis_cpu_time();
double dis_wall_time();
double seq_cpu_time();
double seq_wall_time();
.fi
.PP
 
.SH "EXAMPLE"
.PP
.PP
.nf
    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
.fi
.PP
 See also \fBdiststream(2)\fP for \fCderr\fP\&.
.SH "DESCRIPTION"
.PP
\fCdis_cpu_time\fP 
.PP
.RS 4
Returns the accumulated CPU for all processed linked together via the default communicator\&. 
.RE
.PP
\fCseq_cpu_time\fP 
.PP
.RS 4
It is similar but returns the computing time per user for the current process only\&. 
.RE
.PP
\fCdis_wall_time\fP 
.PP
.RS 4
Returns a floating-point number of seconds, representing elapsed wall-clock time since some time in the past\&. The \fItime in the past\fP 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 \fIticks\fP), it allows high resolution, and carries no unnecessary baggage\&. In a distributed environment, \fCdis_wall_time\fP clocks are synchronized: different nodes return the same time value at the same instant\&. 
.RE
.PP
\fCseq_wall_time\fP 
.PP
.RS 4
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 \fCseq_wall_time\fP is reached\&. 
.RE
.PP
.SH "IMPLEMENTATION"
.PP
This documentation has been generated from file linalg/lib/dis_cpu_time\&.h 
.SH AUTHOR
Pierre  Saramito  <Pierre.Saramito@imag.fr>
.SH 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.