hadroNIO: Accelerating Java NIO via UCX
Fabian Ruhland, Filip Krakowski, Michael Schöttner · 2021
InfiniBand networks with bandwidths up to 400 Gbit/s and sub-microsecond latencies are more and more popular in HPC and cloud data centers. Many big-data frameworks, such as Apache Spark and Cassandra, are written in Java and use Java NIO socket channels, which are designed for Ethernet networks. Rewriting network code for such complex systems is typically not an option and thus, transparent solutions like IP over InfiniBand are used.In this paper, we present hadroNIO, a Java library, that transparently replaces the default NIO implementation, providing support for InfiniBand (as well as Ethernet and other transports) through the Unified Communication X (UCX) library. We compare our library against other transparent network acceleration solutions in an InfiniBand environment and also evaluate the overhead, that is introduced by using hadroNIO versus directly accessing UCX. We show that it is possible to achieve latencies as low as 3.1 μs, while also being able to leverage the full bandwidth of InfiniBand hardware with our fully transparent acceleration solution. In the future we aim at extending hadroNIO, and thus the NIO API, with RDMA directives.