Performance Evaluation and Improvements of the PoCL Open-Source OpenCL Implementation on Intel CPUs
- The Portable Computing Language (PoCL) is a vendor independent open-source OpenCL implementation that aims to support a variety of compute devices in a single platform. Evaluating PoCL versus the Intel OpenCL implementation reveals significant performance drawbacks of PoCL on Intel CPUs – which run 92 % of the TOP500 list. Using a selection of benchmarks, we identify and analyse performance issues in PoCL with a focus on scheduling and vectorisation. We propose a new CPU device-driver based on Intel Threading Building Blocks (TBB), and evaluate LLVM with respect to automatic compiler vectorisation across work-items in PoCL. Using the TBB driver, it is possible to narrow the gap to Intel OpenCL and even outperform it by a factor of up to 1.3× in our proxy application benchmark with a manual vectorisation strategy.
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| Author: | Tobias BaumannORCiD, Matthias NoackORCiD, Thomas SteinkeORCiD |
|---|---|
| Document Type: | In Proceedings |
| Parent Title (English): | IWOCL'21: International Workshop on OpenCL |
| Year of first publication: | 2021 |
| DOI: | https://doi.org/10.1145/3456669.3456698 |
