1. Foreword

python-rdma is a project intended to bring IB and RDMA capabilities to the Python language. The main focus is not on high performance communication but rather on effective and correct use of the IB and RDMA protocol stacks.

Primarily python-rdma is well suited for areas where quick development is much more important than high performance:

• IB management software development. This is a significant strength of the module, which incorporates nearly the complete set of management protocols from the IBA specification. Much of the common errors and complexity in management processing (eg byte order, bit slicing, etc) is eliminated through the extensive use of code generation and full structure unpacking. The sophisticated introspection system allows very flexible and comprehensive processing of IBA defined management structures.
• Test development. The simplicity and comprehensiveness of the library can greatly speed development of management and verbs protocol test suites. Several bugs were found and patched in the OFA stack just during the development of the library’s internal test suite.
• Training and problem exploration. Although the interface is quite different from the C APIs the general concepts flow over, and the Python bindings can be used without burdensome explicit error handling.

I also feel it is an fairly comprehensive exploration of an alternative and more integrated API design for IB and RDMA programming. Although several of the constructs are very Python specific, much of the overall organization and principles can carry over to other languages. I feel it would be very interesting to attempt to port the general API to C++, where ease of use and high performance could be combined.

This documentation set attempts to be a complete exploration of the python-rdma module’s capabilities and APIs, but it does assume the reader has significant pre-existing knowledge of the InfiniBand Architecture (IBA) and OFA RDMA Verbs programming and principles.

1.1. Comparison to the OFA C API

For reference the python-rdma module covers the same areas as the following OFA code:

OFA Module	Python-rdma
libibmad	Near 100% coverage via rdma.madtransactor and rdma.IBA
libibumad	100% coverage via rdma.umad
libibverbs	100% coverage via rdma.ibverbs (through Pyrex)
libibnetdisc	~80% coverage. No support for switch chassis grouping.
librdmacm	Not covered
libibcm	Not covered
infiniband-diags	45 commands re-implemented, 2 un-implemented. Review The ibtool Program
ibutils	Good coverage of the internal APIs but no coverage for the user tools.
perftest	rdma_bw is implemented as an example.

Other than rdma.ibverbs all of the module is written in pure Python.