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Subject: Re: [OMPI users] Regarding the execution time calculation
From: Björn Adlerborn (bjorn.adlerborn_at_[hidden])
Date: 2012-05-03 08:59:08

Hi, could you also attach your current code ?





From: users-bounces_at_[hidden] [mailto:users-bounces_at_[hidden]] On
Behalf Of seshendra seshu
Sent: den 3 maj 2012 13:49
To: Open MPI Users
Subject: [OMPI users] Regarding the execution time calculation


I have written an parallel program and when i run my program on 4,8,16 nodes
and calculated the execution time at master using MPI_Wtime in master node.
The problem the execution time is increasing rapidly like NON parallel
program-55 sec, and for parallel program 2-nodes--60sec , 4-nodes 74sec,
8-node--120 sec and for 16 nodes---for 180 sec. can i know my problem in
parallel version actually the time needs to be decreased but it is
increasing i dont the reason. i have calculated my time as shown below

double start,end;
start= MPI_Wtime;
// done some work
// start send from master node and receiving it
end =MPI_Wtime;
cout<<"execution time"<<end-start;
//in slave nodes done some work

Please help me in solving this problem.