COMP Superscalar

New features

• Runtime:
  • Support for http requests (@http decorator).
  • Support for Java versions higher than 8.
  • Enable grouping processes in MPI tasks with the processes_per_node flag.
  • Partial support for OSX systems.
• Python:
  • PyArrow object serialization support.
  • Cache profiling enabled

Improvements:

Known Limitations

• Collections are not supported in http tasks.
• OSX support is limited to Java and Python2 without CPU affinity (require to execute with --cpu_affinity=disable). We have also detected issues when several python3 versions are installed in the system. Tracing is not available.
• Reduce operations can consume more disk space than the manually programmed n-ary reduction
• Objects used as task parameters must be serializable.
• Tasks that invoke Numpy and MKL may experience issues if a different MKL threads count is used in different tasks. This is due to the fact that MKL reuses  threads in the different calls and it does not change the number of threads from one call to another. This can be also happen with other libraries implemented with OpenMP.
• C++ Objects declared as arguments in a coarse-grain tasks must be passed in the task methods as object pointers in order to have a proper dependency management.
• Master as worker is not working for executions with persistent worker in C++.
• Coherence and concurrent writing in parameters annotated with the "Concurrent" direction must be managed by the underlaying distributed storage system.
• Delete file calls for files used as input can produce a significant synchronization of the main code.
• Defining a parameter as OUT is only allowed for files and collection files.
• There is an issue with hwloc and Docker which could affect to python mpi workers. Fixing it require to upgrade the hwloc version used by the MPI runtime.

For further information please refer to COMPSs Documentation