DRAM row buffer conflicts can increase memory access latency significantly. This paper presents a new pageallocation-based optimization that works seamlessly together with some existing hardware and software optimizat...DRAM row buffer conflicts can increase memory access latency significantly. This paper presents a new pageallocation-based optimization that works seamlessly together with some existing hardware and software optimizations to eliminate significantly more row buffer conflicts. Validation in simulation using a set of selected scientific and engineering benchmarks against a few representative memory controller optimizations shows that our method can reduce row buffer miss rates by up to 76% （with an average of 37.4%）. This reduction in row buffer miss rates will be translated into performance speedups by up to 15% （with an average of 5%）.展开更多
GPGPUs are increasingly being used to as performance accelerators for HPC （High Performance Computing） applications in CPU/GPU heterogeneous computing systems, including TianHe-1A, the world＇s fastest supercomputer...GPGPUs are increasingly being used to as performance accelerators for HPC （High Performance Computing） applications in CPU/GPU heterogeneous computing systems, including TianHe-1A, the world＇s fastest supercomputer in the TOP500 list, built at NUDT （National University of Defense Technology） last year. However, despite their performance advantages, GPGPUs do not provide built-in fault-tolerant mechanisms to offer reliability guarantees required by many HPC applications. By analyzing the SIMT （single-instruction, multiple-thread） characteristics of programs running on GPGPUs, we have developed PartialRC, a new checkpoint-based compiler-directed partial recomputing method, for achieving efficient fault recovery by leveraging the phenomenal computing power of GPGPUs. In this paper, we introduce our PartialRC method that recovers from errors detected in a code region by partially re-computing the region, describe a checkpoint-based faulttolerance framework developed on PartialRC, and discuss an implementation on the CUDA platform. Validation using a range of representative CUDA programs on NVIDIA GPGPUs against FullRC （a traditional full-recomputing Checkpoint-Rollback-Restart fault recovery method for CPUs） shows that PartialRC reduces significantly the fault recovery overheads incurred by FullRC, by 73.5% when errors occur earlier during execution and 74.6% when errors occur later on average. In addition, PartialRC also reduces error detection overheads incurred by FullRC during fault recovery while incurring negligible performance overheads when no fault happens.展开更多
In this paper, we present a hybrid circular queue method that can significantly boost the performance of stencil computations on GPU by carefully balancing usage of registers and shared-memory. Unlike earlier methods ...In this paper, we present a hybrid circular queue method that can significantly boost the performance of stencil computations on GPU by carefully balancing usage of registers and shared-memory. Unlike earlier methods that rely on circular queues predominantly implemented using indirectly addressable shared memory, our hybrid method exploits a new reuse pattern spanning across the multiple time steps in stencil computations so that circular queues can be implemented by both shared memory and registers effectively in a balanced manner. We describe a framework that automatically finds the best placement of data in registers and shared memory in order to maximize the performance of stencil computations. Validation using four different types of stencils on three different GPU platforms shows that our hybrid method achieves speedups up to 2.93X over methods that use circular queues implemented with shared-memory only.展开更多
As semi-conductor technologies move down to the nanometer scale, leakage power has become a significant component of the total power consumption. In this paper, we present a leakage-aware modulo scheduling algorithm t...As semi-conductor technologies move down to the nanometer scale, leakage power has become a significant component of the total power consumption. In this paper, we present a leakage-aware modulo scheduling algorithm to achieve leakage energy saving for applications with loops on Very Long Instruction Word （VLIW） architectures. The proposed algorithm is designed to maximize the idleness of function units integrated with the dual-threshold domino logic, and reduce the number of transitions between the active and sleep modes. We have implemented our technique in the Trimaran compiler and conducted experiments using a set of embedded benchmarks from DSPstone and Mibench on the cycle-accurate VLIW simulator of Trimaran. The results show that our technique achieves significant leakage energy saving compared with a previously published DAG-based （Directed Acyclic Graph） leakage-aware scheduling algorithm.展开更多
基金Supported by the National Basic Research 973 Program of China under Grant No. 2005CB321602the National Natural Science Foundation of China under Grant No. 60736012
文摘DRAM row buffer conflicts can increase memory access latency significantly. This paper presents a new pageallocation-based optimization that works seamlessly together with some existing hardware and software optimizations to eliminate significantly more row buffer conflicts. Validation in simulation using a set of selected scientific and engineering benchmarks against a few representative memory controller optimizations shows that our method can reduce row buffer miss rates by up to 76% （with an average of 37.4%）. This reduction in row buffer miss rates will be translated into performance speedups by up to 15% （with an average of 5%）.
基金supported by the National Natural Science Foundation of China under Grant Nos. 60921062, 61003087, 61120106005 and 61170049
文摘GPGPUs are increasingly being used to as performance accelerators for HPC （High Performance Computing） applications in CPU/GPU heterogeneous computing systems, including TianHe-1A, the world＇s fastest supercomputer in the TOP500 list, built at NUDT （National University of Defense Technology） last year. However, despite their performance advantages, GPGPUs do not provide built-in fault-tolerant mechanisms to offer reliability guarantees required by many HPC applications. By analyzing the SIMT （single-instruction, multiple-thread） characteristics of programs running on GPGPUs, we have developed PartialRC, a new checkpoint-based compiler-directed partial recomputing method, for achieving efficient fault recovery by leveraging the phenomenal computing power of GPGPUs. In this paper, we introduce our PartialRC method that recovers from errors detected in a code region by partially re-computing the region, describe a checkpoint-based faulttolerance framework developed on PartialRC, and discuss an implementation on the CUDA platform. Validation using a range of representative CUDA programs on NVIDIA GPGPUs against FullRC （a traditional full-recomputing Checkpoint-Rollback-Restart fault recovery method for CPUs） shows that PartialRC reduces significantly the fault recovery overheads incurred by FullRC, by 73.5% when errors occur earlier during execution and 74.6% when errors occur later on average. In addition, PartialRC also reduces error detection overheads incurred by FullRC during fault recovery while incurring negligible performance overheads when no fault happens.
基金Supported in part by the National Basic Research 973 Program of China under Grant Nos. 2011CB302504 and 2011ZX01028-001-002the National High Technology Research and Development 863 Program of China under Grant No. 2009AA01A129+1 种基金the National Natural Science Foundation of China (NSFC) under Grant No. 60970024the Innovation Research Group of NSFC under Grant No. 60921002
文摘In this paper, we present a hybrid circular queue method that can significantly boost the performance of stencil computations on GPU by carefully balancing usage of registers and shared-memory. Unlike earlier methods that rely on circular queues predominantly implemented using indirectly addressable shared memory, our hybrid method exploits a new reuse pattern spanning across the multiple time steps in stencil computations so that circular queues can be implemented by both shared memory and registers effectively in a balanced manner. We describe a framework that automatically finds the best placement of data in registers and shared memory in order to maximize the performance of stencil computations. Validation using four different types of stencils on three different GPU platforms shows that our hybrid method achieves speedups up to 2.93X over methods that use circular queues implemented with shared-memory only.
基金supported by the National Natural Science Foundation of China under Grant Nos. 60873006 and 61070049the International Collaborative Research Program under Grant No. 2010DFB10930+1 种基金the Beijing Science Foundation under Grant No.KZ200910028007the Australian Research Council (ARC) under Grant No. DP0881330
文摘As semi-conductor technologies move down to the nanometer scale, leakage power has become a significant component of the total power consumption. In this paper, we present a leakage-aware modulo scheduling algorithm to achieve leakage energy saving for applications with loops on Very Long Instruction Word （VLIW） architectures. The proposed algorithm is designed to maximize the idleness of function units integrated with the dual-threshold domino logic, and reduce the number of transitions between the active and sleep modes. We have implemented our technique in the Trimaran compiler and conducted experiments using a set of embedded benchmarks from DSPstone and Mibench on the cycle-accurate VLIW simulator of Trimaran. The results show that our technique achieves significant leakage energy saving compared with a previously published DAG-based （Directed Acyclic Graph） leakage-aware scheduling algorithm.
