Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601954
A. Namazi, M. Nourani
In this paper, we propose a distributed voting strategy to design a robust NMR system. We show that using inexpensive current-based drivers and buffers, we can completely eliminate the centralized voter unit and do the majority voting among N modules in a distributed fashion. Our strategy achieves high reliability that is vital for future nano systems in which high defect rate is expected. Experimental results are also reported to verify the concept, clarify the design procedure and measure the system's reliability.
{"title":"Distributed voting for fault-tolerant nanoscale systems","authors":"A. Namazi, M. Nourani","doi":"10.1109/ICCD.2007.4601954","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601954","url":null,"abstract":"In this paper, we propose a distributed voting strategy to design a robust NMR system. We show that using inexpensive current-based drivers and buffers, we can completely eliminate the centralized voter unit and do the majority voting among N modules in a distributed fashion. Our strategy achieves high reliability that is vital for future nano systems in which high defect rate is expected. Experimental results are also reported to verify the concept, clarify the design procedure and measure the system's reliability.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86418302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601879
Subramanian Ramaswamy, S. Yalamanchili
In this paper we propose techniques to dynamically downsize or upsize a cache accompanied by cache set/line shutdown to produce efficient caches. Unlike previous approaches, resizing is accompanied by a non-uniform remapping of memory into the resized cache, thus avoiding misses to sets/lines that are shut off. The paper first provides an analysis into the causes of energy inefficiencies revealing a simple model for improving efficiency. Based on this model we propose the concept of "folding" - memory regions mapping to disjoint cache resources are combined to share cache sets producing a new placement function. Folding enables powering down cache sets at the expense of possibly increasing conflict misses. Effective folding heuristics can substantially increase energy efficiency at the expense of acceptable increase in execution time. We target the 12 cache because of its larger size and greater energy consumption. Our techniques increase cache energy efficiency by 20%, and reduce the EDP (energy delay product) by up to 45% with an IPC degradation of less than 4%. The results also indicate opportunity for improving cache efficiencies further via cooperative compiler interactions.
{"title":"Improving cache efficiency via resizing + remapping","authors":"Subramanian Ramaswamy, S. Yalamanchili","doi":"10.1109/ICCD.2007.4601879","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601879","url":null,"abstract":"In this paper we propose techniques to dynamically downsize or upsize a cache accompanied by cache set/line shutdown to produce efficient caches. Unlike previous approaches, resizing is accompanied by a non-uniform remapping of memory into the resized cache, thus avoiding misses to sets/lines that are shut off. The paper first provides an analysis into the causes of energy inefficiencies revealing a simple model for improving efficiency. Based on this model we propose the concept of \"folding\" - memory regions mapping to disjoint cache resources are combined to share cache sets producing a new placement function. Folding enables powering down cache sets at the expense of possibly increasing conflict misses. Effective folding heuristics can substantially increase energy efficiency at the expense of acceptable increase in execution time. We target the 12 cache because of its larger size and greater energy consumption. Our techniques increase cache energy efficiency by 20%, and reduce the EDP (energy delay product) by up to 45% with an IPC degradation of less than 4%. The results also indicate opportunity for improving cache efficiencies further via cooperative compiler interactions.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83623566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601952
Eric L. Hill, Mikko H. Lipasti
Prior work has shown that collapsible pipelining techniques have the potential to significantly reduce clocking activity, which can consume up to 70% of the dynamic power in modern high performance microprocessors. Previous collapsible pipeline proposals either rely on single phase clocking (by forcing latches into transparent state) or do not discuss the mechanisms by which stages are merged. In this work two flip-flop designs featuring an additional transparent state suitable for collapsing stages are presented. Transparency is achieved either by decoupling the master and slave clocks to keep both latches transparent, or by using a bypass mux that routes around the flip-flop. Both of these designs are evaluated in the context of transparently gated pipelines, an ad-hoc collapsible pipelining technique. Detailed analysis shows that the decoupled clock flip-flop is the most attractive in terms of energy and delay.
{"title":"Transparent mode flip-flops for collapsible pipelines","authors":"Eric L. Hill, Mikko H. Lipasti","doi":"10.1109/ICCD.2007.4601952","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601952","url":null,"abstract":"Prior work has shown that collapsible pipelining techniques have the potential to significantly reduce clocking activity, which can consume up to 70% of the dynamic power in modern high performance microprocessors. Previous collapsible pipeline proposals either rely on single phase clocking (by forcing latches into transparent state) or do not discuss the mechanisms by which stages are merged. In this work two flip-flop designs featuring an additional transparent state suitable for collapsing stages are presented. Transparency is achieved either by decoupling the master and slave clocks to keep both latches transparent, or by using a bypass mux that routes around the flip-flop. Both of these designs are evaluated in the context of transparently gated pipelines, an ad-hoc collapsible pipelining technique. Detailed analysis shows that the decoupled clock flip-flop is the most attractive in terms of energy and delay.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80065065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601896
Liang-Kai Wang, C. Tsen, M. Schulte, Divya Jhalani
The IEEE P754 draft standard for floating-point arithmetic provides specifications for decimal floating-point (DFP) formats and operations. Based on this standard, many developers will provide support for DFP calculations. We present a benchmark suite for DFP applications and use this suite to evaluate the performance of hardware and software DFP solutions. Our benchmarks include banking, commerce, risk-management, tax, and telephone billing applications organized into a suite of five macro benchmarks. In addition to developing our own applications, we leverage open-source projects and academic financial analysis applications. The benchmarks are modular, making them easy to adapt for different DFP solutions. We use the benchmarks to evaluate the performance of the decNumber DFP library and an extended version of the SimpleScalar PISA architecture with hardware and instruction set support for DFP operations. Our analysis shows that providing processor support for high-speed DFP operations significantly improves the performance of DFP applications.
{"title":"Benchmarks and performance analysis of decimal floating-point applications","authors":"Liang-Kai Wang, C. Tsen, M. Schulte, Divya Jhalani","doi":"10.1109/ICCD.2007.4601896","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601896","url":null,"abstract":"The IEEE P754 draft standard for floating-point arithmetic provides specifications for decimal floating-point (DFP) formats and operations. Based on this standard, many developers will provide support for DFP calculations. We present a benchmark suite for DFP applications and use this suite to evaluate the performance of hardware and software DFP solutions. Our benchmarks include banking, commerce, risk-management, tax, and telephone billing applications organized into a suite of five macro benchmarks. In addition to developing our own applications, we leverage open-source projects and academic financial analysis applications. The benchmarks are modular, making them easy to adapt for different DFP solutions. We use the benchmarks to evaluate the performance of the decNumber DFP library and an extended version of the SimpleScalar PISA architecture with hardware and instruction set support for DFP operations. Our analysis shows that providing processor support for high-speed DFP operations significantly improves the performance of DFP applications.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80833022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601877
Jae W. Lee, Myron King, K. Asanović
Transaction-level modeling (TLM) allows a designer to save functional verification effort during the modular refinement of an SoC by reusing the prior implementation of a module as a golden model for state inconsistency detection. One problem in simulation-based verification is the performance and bandwidth overhead of state dump and comparison between two models. In this paper, we propose an efficient fine-grain state inconsistency detection technique that checks the consistency of two states of arbitrary size at sub- transaction (tick) granularity using incremental hashes. At each tick, the hash generates a signature of the entire state, which can be efficiently updated and compared. We evaluate the proposed signature scheme with a FIR filter and a Vorbis decoder and show that very fine-grain state consistency checking is feasible. The hash signature checking increases execution time of Bluespec RTL simulation by 1.2% for the FIR filter and by 2.2% for the Verbis decoder while correctly detecting any injected state inconsistency.
{"title":"Continual hashing for efficient fine-grain state inconsistency detection","authors":"Jae W. Lee, Myron King, K. Asanović","doi":"10.1109/ICCD.2007.4601877","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601877","url":null,"abstract":"Transaction-level modeling (TLM) allows a designer to save functional verification effort during the modular refinement of an SoC by reusing the prior implementation of a module as a golden model for state inconsistency detection. One problem in simulation-based verification is the performance and bandwidth overhead of state dump and comparison between two models. In this paper, we propose an efficient fine-grain state inconsistency detection technique that checks the consistency of two states of arbitrary size at sub- transaction (tick) granularity using incremental hashes. At each tick, the hash generates a signature of the entire state, which can be efficiently updated and compared. We evaluate the proposed signature scheme with a FIR filter and a Vorbis decoder and show that very fine-grain state consistency checking is feasible. The hash signature checking increases execution time of Bluespec RTL simulation by 1.2% for the FIR filter and by 2.2% for the Verbis decoder while correctly detecting any injected state inconsistency.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77700902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601938
T. Chiang, C. Y. Chen, Weiyu Chen
Accurate estimation of gate delays is essential for timing-related CAD tools. CAD researchers tend to use Elmore delay model for estimating gate delays. Since Elmore delay model was primarily developed for estimating interconnection delay, when applied to gate delay estimation, there will be significant inaccuracy. In this paper, by embedding concepts of electronic theories into switch-level analysis, a simple and efficient delay model for gates of general types (such as NAND, NOR, and complex gates) is proposed. Experimental data show that the proposed gate delay model consistently achieves high accuracy (typically within around 2% of SPICE simulations).
{"title":"An efficient gate delay model for VLSI design","authors":"T. Chiang, C. Y. Chen, Weiyu Chen","doi":"10.1109/ICCD.2007.4601938","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601938","url":null,"abstract":"Accurate estimation of gate delays is essential for timing-related CAD tools. CAD researchers tend to use Elmore delay model for estimating gate delays. Since Elmore delay model was primarily developed for estimating interconnection delay, when applied to gate delay estimation, there will be significant inaccuracy. In this paper, by embedding concepts of electronic theories into switch-level analysis, a simple and efficient delay model for gates of general types (such as NAND, NOR, and complex gates) is proposed. Experimental data show that the proposed gate delay model consistently achieves high accuracy (typically within around 2% of SPICE simulations).","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79487681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601928
M. Hamada, T. Kitahara, N. Kawabe, Hironori Sato, T. Nishikawa, T. Shimazawa, T. Yamashita, H. Hara, Y. Oowaki
An automated runtime power-gating scheme to reduce the leakage power in the active mode is presented in this paper. We propose a circuit that generates a sleep control signal from a clock-gating control signal automatically. By the combination of selective MT-CMOS scheme, the generated sleep control signal, and a novel flip-flop circuit with an additional latch function, a zero-wait transition from a sleep mode to an active mode is enabled. The additional latch function required for the zero-wait transition is achieved by only 6 transistors in addition to a conventional flip- flop. By the scheme, any design with the clock-gating scheme can be transformed automatically to a power- gated design while keeping the system operation the same in terms of the cycle accuracy. The scheme is applied to an MPEG4/H.264 audio/video codec and 21% power saving is achieved in the active mode while keeping the area overhead only 16% in a 90 nm CMOS design.
{"title":"An automated runtime power-gating scheme","authors":"M. Hamada, T. Kitahara, N. Kawabe, Hironori Sato, T. Nishikawa, T. Shimazawa, T. Yamashita, H. Hara, Y. Oowaki","doi":"10.1109/ICCD.2007.4601928","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601928","url":null,"abstract":"An automated runtime power-gating scheme to reduce the leakage power in the active mode is presented in this paper. We propose a circuit that generates a sleep control signal from a clock-gating control signal automatically. By the combination of selective MT-CMOS scheme, the generated sleep control signal, and a novel flip-flop circuit with an additional latch function, a zero-wait transition from a sleep mode to an active mode is enabled. The additional latch function required for the zero-wait transition is achieved by only 6 transistors in addition to a conventional flip- flop. By the scheme, any design with the clock-gating scheme can be transformed automatically to a power- gated design while keeping the system operation the same in terms of the cycle accuracy. The scheme is applied to an MPEG4/H.264 audio/video codec and 21% power saving is achieved in the active mode while keeping the area overhead only 16% in a 90 nm CMOS design.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74352673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601912
E. Wong, S. Lim
One of the biggest challenges in 3D stacked IC design is heat dissipation. Incorporating thermal vias is a promising method for reducing the temperatures of 3D ICs. The bonding styles between device layers impose certain restrictions to where thermal vias may be inserted. This paper presents a whitespace redistribution algorithm that takes bonding style into consideration to improve thermal via placement, which in turn reduces temperature.
{"title":"Whitespace redistribution for thermal via insertion in 3D stacked ICs","authors":"E. Wong, S. Lim","doi":"10.1109/ICCD.2007.4601912","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601912","url":null,"abstract":"One of the biggest challenges in 3D stacked IC design is heat dissipation. Incorporating thermal vias is a promising method for reducing the temperatures of 3D ICs. The bonding styles between device layers impose certain restrictions to where thermal vias may be inserted. This paper presents a whitespace redistribution algorithm that takes bonding style into consideration to improve thermal via placement, which in turn reduces temperature.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88296748","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601888
Erika Gunadi, Mikko H. Lipasti
This paper presents the finished store buffer (or FSB), an alternative and position-insensitive approach for building a scalable store buffer for an out-of-order processor. Exploiting the fact that only a small portion of in-flight stores are done executing (i.e. finished) and waiting for retirement, we are able to build a much smaller and more scalable store buffer. Our study shows that we only need at most half of the number of entries in a conventional store queue if we buffer only the stores that have finished execution. Entries in the store buffer are allocated at issue and disallocated on retirement. A clever encoder circuit is used to provide positional searches without an explicitly positional queue structure. While reducing the access latency and power consumption significantly, our technique has virtually no detrimental effect on per-cycle performance (IPC).
{"title":"A position-insensitive finished store buffer","authors":"Erika Gunadi, Mikko H. Lipasti","doi":"10.1109/ICCD.2007.4601888","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601888","url":null,"abstract":"This paper presents the finished store buffer (or FSB), an alternative and position-insensitive approach for building a scalable store buffer for an out-of-order processor. Exploiting the fact that only a small portion of in-flight stores are done executing (i.e. finished) and waiting for retirement, we are able to build a much smaller and more scalable store buffer. Our study shows that we only need at most half of the number of entries in a conventional store queue if we buffer only the stores that have finished execution. Entries in the store buffer are allocated at issue and disallocated on retirement. A clever encoder circuit is used to provide positional searches without an explicitly positional queue structure. While reducing the access latency and power consumption significantly, our technique has virtually no detrimental effect on per-cycle performance (IPC).","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84569864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-10-01DOI: 10.1109/ICCD.2007.4601925
Jianxun Liu, W. Jone
This paper presents a powerful routing method for pseudo-exhaustive built-in self-testing of high-speed interconnects with both capacitive and inductive crosstalk effects. Based on the concepts of test cone and cut-off locality, the routing method can generate an interconnect structure such that all nets can be tested by pseudoexhaustive patterns. The test pattern generation method is simple and efficient. Experimental results obtained by simulating a set of MCNC benchmarks demonstrate the feasibility of the proposed pseudo-exhaustive test approach and the efficiency of the proposed routing method.
{"title":"An efficient routing method for pseudo-exhaustive built-in self-testing of high-speed interconnects","authors":"Jianxun Liu, W. Jone","doi":"10.1109/ICCD.2007.4601925","DOIUrl":"https://doi.org/10.1109/ICCD.2007.4601925","url":null,"abstract":"This paper presents a powerful routing method for pseudo-exhaustive built-in self-testing of high-speed interconnects with both capacitive and inductive crosstalk effects. Based on the concepts of test cone and cut-off locality, the routing method can generate an interconnect structure such that all nets can be tested by pseudoexhaustive patterns. The test pattern generation method is simple and efficient. Experimental results obtained by simulating a set of MCNC benchmarks demonstrate the feasibility of the proposed pseudo-exhaustive test approach and the efficiency of the proposed routing method.","PeriodicalId":6306,"journal":{"name":"2007 25th International Conference on Computer Design","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2007-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89565720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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