Mota is a library that provides several heuristics for mapping tasks to compute ranks (processes) on a networked computer cluster or supercomputer. It was originally designed for task placement of adaptive mesh refinement codes (AMR). It is multi-objective in the sense that it simultaneously balances (potentially multiple types of) computational load on each rank as well as the communication traffic between the boxes. The heuristics used for mapping include algorithms such as list assignment and space-filling curves, as well as algorithms from graph analysis such as adjacency matrix bandwidth reduction, recursive bisection, and greedy placement.
Mota has been used in conjunction with ProgrAMR and SST/Macro for the purpose of simulating AMR performance on future network interconnection topologies and is being integrated into the AMReX framework for box placement during dynamic regridding. We utilize switch-link topology models for current and future supercomputer network interconnects to do task placement and make a detailed evaluation of the network utilization and performance.
- C++11 compliant compiler
- External codes:
- To create a network graph, call factory funcction
net_graph_create(std::string label, int cons_n, const RanksByCartesian<4> &ranks_by_coord)to create a network graph of typelabel, whose nodes are assigned ranks byranks_by_coord, and have capacities forcons_nconstraints. - See
src/netmodels.hxxfor more details
- To create an application graph, call factory function
app_graph_create(int cons_n), withcons_nset to the number of constraints desired (e.g. number of AMR levels that require load balancing) - To specify the nodes and edges in the application graph, call
AppGraph_::import() - To map the application graph to a network graph, call
AppGraph_::run_mapper() - See
src/appgraph.hxxfor more details
"Mota Mapper: A Multi-Objective Topology-Aware Mapper Library (Mota) v1.0" Copyright (c) 2018, The Regents of the University of California, through Lawrence Berkeley National Laboratory (subject to receipt of any required approvals from the U.S. Dept. of Energy). All rights reserved.
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