Exploring and Evaluating MPI Support on P4 Programmable Switches

For a tutorial on compiling and running mpitofino, skip ahead to mpitofino.

This is the main repository for our work on mpitofino, a software stack to offload integer aggregation onto Tofino switches (so-called in-network computing, or in-fabric computing).

In addition to the actual mpitofino software suite, it houses additional information and tools.

It is available from https://github.com/erbth/mpitofino.

Repository structure

evaluation

This directory contains the experimental results used for the thesis, and additional profiling-results gathered while optimizing the code.

other_work

A 'scratchpad' to persist thoughts that indirectly influenced the work

projects

The actual codebase, split into different 'subprojects', lives in this repository. It is organized into the following subdirectories:

• allreduce_poc: An early proof-of-concept for implementing the allreduce collective communicaiton primitive on Tofino. It uses a direct ethernet-based transport and has all runtime parameters hardcoded. It might be useful to understand/test the basic concept without the complex dynamic resource allocation and RoCE transport of mpitofino, but probably not for much more.

• microbenchmarks: Microbenchmarks/test that use OpenMPI to evaluate mpitofino on a system level (therefore using OpenMPI and not e.g. mpitofino's internal API)

• mpitofino: The actual core system containing the P4-code, control plane, and an example client which uses mpitofino's internal API to test/evaluate the core system.

• openmpi: The OpenMPI integration, which makes mpitofino available as a so-called component in OpenMPI's modular component architecture.

• tools: Additional tools required to run the system.

third_party

Third party repositories used in/with mpitofino. Currently this contains a only OpenMPI version 4.8.1 as a git-submodule. It is used as a basis for our patches that add support for mpitofino to OpenMPI.

Hence make sure to clone this repository with git clone --recursive, or download the submodule using git submodule update --init if you already cloned the repository without --recursive.