Title: A small and power efficient checkpoint core architecture for manycore processors

Authors: Mageda Sharafeddin; Haitham Akkary

Addresses: Department of Electrical and Computer Engineering, American University of Beirut, P.O. Box 11-0236, Riad El-Solh, Beirut 1107 2020, Lebanon ' Department of Electrical and Computer Engineering, American University of Beirut, P.O. Box 11-0236, Riad El-Solh, Beirut 1107 2020, Lebanon

Abstract: This article describes and evaluates a small, out-of-order, simultaneous multithreaded (SMT) core architecture suitable for power constrained microprocessors, such as manycore microprocessors for high performance computing. The architecture does not require a reorder buffer (ROB) or physical registers for register renaming and instruction retirement. Instead, it uses a large number of virtual register IDs for register renaming, and a logical register file with multiple contexts. The architecture improves total thread execution throughput using two register contexts to support SMT execution of parallel workloads. Moreover, the architecture improves instruction level parallelism (ILP) and execution performance when running single-thread applications. In addition to eliminating the reorder buffer and the physical renaming register file, the architecture minimises the logical register file hardware by using the two SMT register contexts and in-cell register file context fusion mechanism for recovering from branch mispredictions. We present results from Spec 2006 benchmarks running on a SimpleScalar performance simulator of our architecture. Our simulation measurements show 5% single-thread performance improvement and 9.6% 2-thread SMT performance improvement over a conventional SMT core architecture with reorder buffer.

Keywords: checkpoint core architectures; out-of-order processors; virtual register renaming; simultaneous multithreading; energy efficiency; manycore processors; power constrained microprocessors; instruction level parallelism; ILP; simulation.

DOI: 10.1504/IJHPSA.2015.072852

International Journal of High Performance Systems Architecture, 2015 Vol.5 No.4, pp.216 - 227

Available online: 04 Nov 2015 *

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