Presentation
MPI Collectives with Programmable Smart Switches
DescriptionProgrammable smart network devices are heavily used by cloud providers, but typically not for HPC. However, they provide opportunities for off-loading computations, in particular for collective operations, which are important for data intensive workloads in classic HPC and ML training. In this paper, we present a prototype called mpitofino to enable offloading MPI collectives (in particular reductions) onto smart switches over an Ethernet fabric. We target Intel’s programmable Ethernet switches equipped with a Tofino ASIC, and we use the P4 programming language to process collective packets on the chip’s low-latency data path. We demonstrate how the flexibility of P4 enables us to use RoCEv2 as protocol, utilizing RDMA hardware support on the nodes’ NICs. Furthermore, we implement mpitofino as a collective provider in Open MPI and discuss its desirable scaling characteristics. Finally, we demonstrate that mpitofino can achieve data throughput close to the 100GBit/s line rate.
Event Type
Workshop
TimeSunday, 16 November 202512:00pm - 12:30pm CST
Location260