Designing a High Performance OpenSHMEM Implementation Using Universal Common Communication Substrate as a Communication Middleware

Proceedings of the 8th International Conference on Partitioned Global Address Space Programming Models

et al. 2014

Self Cite

OpenSHMEM is an open standard for SHMEM libraries.With the standardisation process complete, the community is looking towards extending the API for increasing programmer flexibility and extreme scalability. According to the current OpenSHMEM specification (revision 1.1), allocation of symmetric memory is collective across all PEs executing the application. For better work sharing and memory utilisation, we are proposing the concepts of teams and spaces for OpenSHMEM that together allow allocation of memory only across user-specified teams. Through our implementation we show that by using teams we can confine memory allocation and usage to only the PEs that actually communicate via symmetric memory. We provide our preliminary results that demonstrate creating spaces for teams allows for less consumption of memory resources than the current alternative. We also examine the impact of our extensions on Scalable Synthetic Compact Applications #3 (SSCA3), which is a sensor processing and knowledge formation kernel involving file I/O, and show that up to 30% of symmetric memory allocation can be eliminated without affecting the correctness of the benchmark.

Section: Discussionmentioning

confidence: 99%

Section: Implementation Using Uccsmentioning

confidence: 99%

Section: Designmentioning

confidence: 99%

See 1 more Smart Citation

Extending the OpenSHMEM Memory Model to Support User-Defined Spaces

Welch

Pophale²,

Proceedings of the 8th International Conference on Partitioned Global Address Space Programming Models

et al. 2014

Self Cite

“…For example, OpenSHMEM-UCCS [2] [3], which is a high-performance implementation of the OpenSHMEM specification, implements the SWAP operations and 32 bit AMOs for Mellanox InfiniBand and Cray Gemini interconnects through 64bit CSWAP operation that is supported in hardware.…”

Section: Using Existing Hardware Amos As Building Blocksmentioning

confidence: 99%

Development and Extension of Atomic Memory Operations in OpenSHMEM

Proceedings of the 8th International Conference on Partitioned Global Address Space Programming Models

Venkata

Poole

et al. 2014

Self Cite

A distinguishing characteristic of OpenSHMEM compared to other PGAS programming model implementations is its support for atomic memory operations (AMOs). It provides a rich set of AMO interfaces supporting 32-bit and 64-bit datatypes. On most modern networks, network-implemented AMOs are known to outperform software-implemented AMOs. So, for achieving high-performance, an OpenSHMEM implementation should try to offload AMOs to the underlying network hardware when possible. Nevertheless, the challenge arises when (a) underlying hardware does not support full set of atomic operations, (b) more that one device is used, and (c) heterogeneous systems with multiple types of devices are involved. In this paper, we analyze the challenges and discuss potential solutions to address these challenges.

“…Non-exclusive copying or redistribution is allowed, provided that the article citation is given and the authors and agency are clearly identified as its source. OpenSHMEM open source availability enables users to research and develop new capabilities (extensions) in Open-SHMEM [4].…”

Section: Introductionmentioning

confidence: 99%

OpenSHMEM Reference Implementation using UCCS-uGNI Transport Layer

Janjusic

Proceedings of the 8th International Conference on Partitioned Global Address Space Programming Models

Venkata

et al. 2014

Self Cite

OpenSHMEM is a library interface implementation and specification that enables the implementation of the Partitioned Global Address Space (PGAS) model. It exports modern RDMA network functionality and communication semantics to applications very efficiently. There are many closed source implementations of OpenSHMEM for modern RDMA interconnects such as InfiniBand and Cray's Gemini and Aries. Given the important role that Cray systems play in HPC, in this paper, we present an open source implementation of OpenSHMEM for Cray XE/XK/XC systems.To implement OpenSHMEM, we use the uGNI interface. uGNI is a generic interface that is designed for multiple programming models. The interface fits well the goal of UCCS. Having OpenSHMEM with UCCS-uGNI allows usage of the same implementation over multiple interconnects. This also translates into many advantages that come with common code such as resource sharing, increasing productivity because of less code maintenance, etc. Preliminary results show that OpenSHMEM-UCCS performs comparable to state-of-the-art Cray SHMEM for Put, Get, and AMO operations.