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Subject: [OMPI users] Difference between read and write performance
From: Ammar Ahmad Awan (ammar.ahmad.awan_at_[hidden])
Date: 2012-07-08 22:03:47

Dear All,

I am working on a micro-bechmarking code based on MPI. My program
writes a 256 million integers array to a file using multiple
processes. It reads the file back into the program using multiple
processes too. The problem is that there is a huge difference between
read and write performances.

Write Time: 182609 micro-seconds
Read Time : 20196 micro-seconds

The test system is a cluster comprising on 32 nodes and each node is
based on intel xeon. The file system is Network File System(NFSv3).
Has anyone else experience the same problem or can any one explain why
there is this big gap b/w the read and write performance?

Kind Regards
-- Ammar
Masters Student
Dept. Of Computer Engineering,
Kyung Hee University