Desynchronized traces in COMPSs

Question

I am generating traces of my executions using COMPSs 1.4. I have noticed that some tasks with data dependencies among them overlap in the tracefile. This shouldn't not be possible. I also checked the dependencies graph and they seem to be correct.

I installed COMPSs following this instructions:

https://stackoverflow.com/a/38568213/2221409

Is there something I can do to synchronize the traces?, should I try to manually sync the clocks of the different machines?

Answer 1

COMPSs' tracing system used to try to sync the traces of the different nodes. However, this feature does not produce good results on most of the machines (that feature will be removed on next release). Usually, you are better off disabling the synchronization.

Edit the file (assuming it's installed on the default paths) /opt/COMPSs/Runtime/scripts/system/trace.sh and edit the following line:

$extraeDir/bin/mpi2prv -f TRACE.mpits -o ./trace/${appName}_compss_trace_${sec}.prv

adding the -no-syn param:

$extraeDir/bin/mpi2prv -no-syn -f TRACE.mpits -o ./trace/${appName}_compss_trace_${sec}.prv

Having said that, more synchronized resources will produce better tracefiles.