[mpich-discuss] MPI_Send and MPI_Bcast
msi at anl.gov
Wed Sep 7 08:18:38 CDT 2016
Generally, for small number of processes, the performance of MPI_Bcast is usually equal to MPI_Isend/MPI_Recv, for large number of processes, broadcast should be better.
Could you please try the lateat version of MPICH on you system ? MPICH2 is very old.
Please also give us following information.Number of processesNumber of processes per nodeThe execution time of each algorithm
Sent via my cell phone.
-------- Original message --------
From: alaa nashar <nashar_al at yahoo.com>
Date: 9/7/2016 7:04 AM (GMT-06:00)
To: discuss at mpich.org
Subject: [mpich-discuss] MPI_Send and MPI_Bcast
implemented the following two algorithms on my home Ethernet LAN containing 2/
and three heterogeneous devices using MPICH2.
process reads the contents of an input array.
then sends the array data to all other processes.
processes including the root process perform specific
computations on their array copies.
the computations within each process are finished,
the generated arrays are directly written by the process that
performed the computations to separate files.
Algorithm 1 except step 2 is replace by:
2- Root process broadcast the array data to all other processes.
implementation of both algorithms work fine and give the expected results
but Algorithm2 that uses MIPI_Bcast is slower than Algorithm1 that uses
knowledge, MIPI_Bcast is faster than MPI_Send.
would you guide me to know if there is any conflict of misunderstand.
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