Hitting the memory wall: implications of the obvious
ACM SIGARCH Computer Architecture News
Simultaneous multithreading: maximizing on-chip parallelism
ISCA '95 Proceedings of the 22nd annual international symposium on Computer architecture
Increasing superscalar performance through multistreaming
PACT '95 Proceedings of the IFIP WG10.3 working conference on Parallel architectures and compilation techniques
ISCA '96 Proceedings of the 23rd annual international symposium on Computer architecture
The case for a single-chip multiprocessor
Proceedings of the seventh international conference on Architectural support for programming languages and operating systems
Memory-system design considerations for dynamically-scheduled processors
Proceedings of the 24th annual international symposium on Computer architecture
Wattch: a framework for architectural-level power analysis and optimizations
Proceedings of the 27th annual international symposium on Computer architecture
Speculative precomputation: long-range prefetching of delinquent loads
ISCA '01 Proceedings of the 28th annual international symposium on Computer architecture
Handling long-latency loads in a simultaneous multithreading processor
Proceedings of the 34th annual ACM/IEEE international symposium on Microarchitecture
Basic Block Distribution Analysis to Find Periodic Behavior and Simulation Points in Applications
Proceedings of the 2001 International Conference on Parallel Architectures and Compilation Techniques
Runahead Execution: An Alternative to Very Large Instruction Windows for Out-of-Order Processors
HPCA '03 Proceedings of the 9th International Symposium on High-Performance Computer Architecture
Microarchitecture Optimizations for Exploiting Memory-Level Parallelism
Proceedings of the 31st annual international symposium on Computer architecture
Mitigating Amdahl's Law through EPI Throttling
Proceedings of the 32nd annual international symposium on Computer Architecture
Techniques for Efficient Processing in Runahead Execution Engines
Proceedings of the 32nd annual international symposium on Computer Architecture
High-Performance Throughput Computing
IEEE Micro
A Memory-Level Parallelism Aware Fetch Policy for SMT Processors
HPCA '07 Proceedings of the 2007 IEEE 13th International Symposium on High Performance Computer Architecture
MLP-Aware Runahead Threads in a Simultaneous Multithreading Processor
HiPEAC '09 Proceedings of the 4th International Conference on High Performance Embedded Architectures and Compilers
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Runahead Threads (RaT) is a promising solution that enables a thread to speculatively run ahead and prefetch data instead of stalling for a long-latency load in a simultaneous multithreading processor. With this capability, RaT can reduces resource monopolization due to memory-intensive threads and exploits memory-level parallelism, improving both system performance and single-thread performance. Unfortunately, the benefits of RaT come at the expense of increasing the number of executed instructions, which adversely affects its energy efficiency. In this paper, we propose Runahead Distance Prediction (RDP), a simple technique to improve the efficiency of Runahead Threads. The main idea of the RDP mechanism is to predict how far a thread should run ahead speculatively such that speculative execution is useful. By limiting the runahead distance of a thread, we generate efficient runahead threads that avoid unnecessary speculative execution and enhance RaT energy efficiency. By reducing runahead-based speculation when it is predicted to be not useful, RDP also allows shared resources to be efficiently used by non-speculative threads. Our results show that RDP significantly reduces power consumption while maintaining the performance of RaT, providing better performance and energy balance than previous proposals in the field.