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The emergence of power as a first-class design constraint has fueled the proposal of a growing number of run-time power optimizations. Many of these optimizations trade-off power saving opportunity for a variable performance loss which depends on application characteristics and program phase. Furthermore, the potential benefits of these optimizations are sometimes non-additive, and it can be difficult...
Technology scaling in integrated circuits has consistently provided dramatic performance improvements in modern microprocessors. However, increasing device counts and decreasing on-chip voltage levels have made transient errors a first-order design constraint that can no longer be ignored. Several proposals have provided fault detection and tolerance through redundantly executing a program on an additional...
Power has become a primary concern for HPC systems. Dynamic voltage and frequency scaling (DVFS) and dynamic concurrency throttling (DCT) are two software tools (or knobs) for reducing the dynamic power consumption of HPC systems. To date, few works have considered the synergistic integration of DVFS and DCT in performance-constrained systems, and, to the best of our knowledge, no prior research has...
This paper presents an energy management policy for reconfigurable clusters running a multi-tier application, exploiting DVS together with multiple sleep states. We develop a theoretical analysis of the corresponding power optimization problem and design an algorithm around the solution. Moreover, we rigorously investigate selection of the optimal number of spare servers for each power state, a problem...
Cache sharing among processors is important for Chip Multiprocessors to reduce inter-thread latency, but also brings cache contention, degrading program performance considerably. Recent studies have shown that job co-scheduling can effectively alleviate the contention, but it remains an open question how to efficiently find optimal co-schedules. Solving the question is critical for determining the...
Chip Multiprocessors (CMPs) allow different applications to concurrently execute on a single chip. When applications with differing demands for memory compete for a shared cache, the conventional LRU replacement policy can significantly degrade cache performance when the aggregate working set size is greater than the shared cache. In such cases, shared cache performance can be significantly improved...
The Cell BE processor is a heterogeneous multicore that contains one PowerPC Processor Element (PPE) and eight Synergistic Processor Elements (SPEs). Each SPE has a small software-managed local store. Applications must explicitly control all DMA transfers of code and data between the SPE local stores and the main memory, and they must perform any coherence actions required for data transferred. The...
Ease of programming is one of the main impediments for the broad acceptance of multi-core systems with no hardware support for transparent data transfer between local and global memories. Software cache is a robust approach to provide the user with a transparent view of the memory architecture; but this software approach can suffer from poor performance. In this paper, we propose a hierarchical, hybrid...
Massively parallel machines that integrate a large number of simple processors and small scratch-pad memories (SPMs) into a single chip can achieve a high peak performance per watt of power. In these machines, communication optimizations are important because the communication bandwidth tends to be a bottleneck. Previously proposed communication optimizations using copy candidates, which have been...
Communication overheads are one of the fundamental challenges in a multiprocessor system. As the number of processors on a chip increases, communication overheads and the distribution of computation and data become increasingly important performance factors. Explicit Dataflow Graph Execution (EDGE) processors, in which instructions communicate with one another directly on a distributed substrate,...
We design and implement Mars, a MapReduce framework, on graphics processors (GPUs). MapReduce is a distributed programming framework originally proposed by Google for the ease of development of web search applications on a large number of commodity CPUs. Compared with CPUs, GPUs have an order of magnitude higher computation power and memory bandwidth, but are harder to program since their architectures...
Recently, chip multiprocessors (CMPs) have arisen as the de facto design for modern high-performance processors, with increasing core counts. An important property of CMPs is that remote, but on-chip, L2 cache accesses are less costly than off-chip accesses; this is in contrast to earlier chip-to-chip or board-to-board multiprocessors, where an access to a remote node is just as costly if not more...
This paper presents the Distributed Cooperative Caching, a scalable and energy-efficient scheme to manage chip multiprocessor (CMP) cache resources. The proposed configuration is based in the Cooperative Caching framework [3] but it is intended for large scale CMPs. Both centralized and distributed configurations have the advantage of combining the benefits of private and shared caches. In our proposal,...
In a hardware transactional memory system with lazy versioning and lazy conflict detection, the process of transaction commit can emerge as a bottleneck. This is especially true for a large-scale distributed memory system where multiple transactions may attempt to commit simultaneously and co-ordination is required before allowing commits to proceed in parallel. In this paper, we propose novel algorithms...
I/O prefetching has been employed in the past as one of the mechanisms to hide large disk latencies. However, I/O prefetching in parallel applications is problematic when multiple CPUs share the same set of disks due to the possibility that prefetches from different CPUs can interact on shared memory caches in the I/O nodes in complex and unpredictable ways. In this paper, we (i) quantify the impact...
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