[mvapich-discuss] Buffering of STDOUT with MVAPICH.

[Peter Diener]

Hi,

I'm trying to debug a parallel code the old fashioned way by inserting
print statements. However, it seems that STDOUT are buffered by MPI on all
processors except processor 0. This happens even though we have a command
line option to do unbuffered or line buffered output from the code. This
makes it hard to figure out when and on which processor the problem 
occurs.

Is it true that MVAPICH does this kind of buffering? And if so, is there a 
way to turn it off?

I'm using MVAPICH version 0.9.8 on an opteron cluster with infiniband 
interconnect.

The code is started with mpiexec.

Cheers,

  Peter