Totalview® for HPC User Guide : PART IV Advanced Tools and Customization : Chapter 22 Scalability in HPC Computing Environments : MRNet
MRNet
MRNet stands for “Multicast/Reduction Network.” MRNet uses a tree-based front-end to back-end communication model to significantly improve the efficiency of data multicast and aggregation for front-end tools running on massively parallel systems.
The following description is from the MRNet web site (http://www.paradyn.org/mrnet/):
MRNet is a software overlay network that provides efficient multicast and reduction communications for parallel and distributed tools and systems. MRNet uses a tree of processes between the tool's front-end and back-ends to improve group communication performance. These internal processes are also used to distribute many important tool activities, reducing data analysis time and keeping tool front-end loads manageable.
MRNet-based tool components communicate across logical channels called streams. At MRNet internal processes, filters are bound to these streams to synchronize and aggregate dataflows. Using filters, MRNet can efficiently compute averages, sums, and other more complex aggregations and analyses on tool data. MRNet also supports facilities that allow tool developers to dynamically load new tool-specific filters into the system.
Rogue Wave’s use of MRNet is part of a larger strategy to improve the scalability of TotalView as high-end computers grow into very high process and thread counts.
TotalView supports MRNet on Linux x86_64, Linux ARM64, and Linux Power clusters, IBM Blue Gene, and Cray XT, XE, and XK.