[Beowulf] mpirun and line buffering

Daniel Kidger daniel.kidger at bull.co.uk
Mon Oct 26 08:35:35 PDT 2009


I have an benchmark code that uses printf  on each MPI process to print 
performance figures.
On the system that the original author's developed on, the output from 
each process must have been line buffereed.

On the QDR IB system I have testing on, the printf from each process is 
not line buffered and so the output is largely unreadable as all the 
lines have been jumbled together.

Is this a known issue with a workaround? or does everyone else only 
print from just one MPI process?


Bull, Architect of an Open World TM

Dr. Daniel Kidger, HPC Technical Consultant
daniel.kidger at bull.co.uk
+44 (0) 7966822177

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