TOD-Tree: Task-Overlapped Direct send Tree Image Compositing for Hybrid MPI Parallelism

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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
The Eurographics Association
Abstract
Modern supercomputers have very powerful multi-core CPUs. The programming model on these supercomputer is switching from pure MPI to MPI for inter-node communication, and shared memory and threads for intra-node communication. Consequently the bottleneck in most systems is no longer computation but communication between nodes. In this paper, we present a new compositing algorithm for hybrid MPI parallelism that focuses on communication avoidance and overlapping communication with computation at the expense of evenly balancing the workload. The algorithm has three stages: a direct send stage where nodes are arranged in groups and exchange regions of an image, followed by a tree compositing stage and a gather stage. We compare our algorithm with radix-k and binary-swap from the IceT library in a hybrid OpenMP/MPI setting, show strong scaling results and explain how we generally achieve better performance than these two algorithms.
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@inproceedings{
10.2312:pgv.20151157
, booktitle = {
Eurographics Symposium on Parallel Graphics and Visualization
}, editor = {
C. Dachsbacher and P. Navrátil
}, title = {{
TOD-Tree: Task-Overlapped Direct send Tree Image Compositing for Hybrid MPI Parallelism
}}, author = {
Grosset, A. V. Pascal
and
Prasad, Manasa
and
Christensen, Cameron
and
Knoll, Aaron
and
Hansen, Charles
}, year = {
2015
}, publisher = {
The Eurographics Association
}, ISBN = {}, DOI = {
10.2312/pgv.20151157
} }
Citation