Simulation environments are an indispensable tool in the design, prototyping, performance evaluation, and analysis of computer systems. Simulator must be able to faithfully reflect the behavior of the system being analyzed. To ensure the accuracy of the simulator, it must be verified and determined to closely match empirical data. Modern processors provide enough performance counters to validate the majority of the performance models; nevertheless, the information provided is not enough to validate power and thermal models.In order to address some of the difficulties associated with the validation of power and thermal models, this paper proposes an infrared measurement setup to capture run-time power consumption and thermal characteristics of modern chips. We use infrared cameras with high spatial resolution (10x10μm) and high frame rate (125fps) to capture thermal maps. To generate a detailed power breakdown (leakage and dynamic) for each processor floorplan unit, we employ genetic algorithms. The genetic algorithm finds a power equation for each floorplan block that produces the measured temperature for a given thermal package. The difference between the predicted power and the externally measured power consumption for an AMD Athlon analyzed in this paper has less than 1% discrepancy. As an example of applicability, we compare the obtained measurements with CACTI power models, and propose extensions to existing thermal models to increase accuracy.

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Design complexity is rapidly becoming a limiting factor in the design of modern, high-performance microprocessors. This paper introduces an optimization technique to improve the efficiency of complex processors. Using a new metric (µUtilization), the designer can identify infrequently-used functionality which contributes little to performance and then systematically "prune" it from the design. For cases in which architectural pruning may affect design correctness, previously proposed techniques can be applied to guarantee forward progress. To explore the benefits of architectural pruning, we study a candidate Optimistic-Checker Tandem architecture, which combines a complex Alpha EV6-like out-of-order Optimistic core, with some of the underutilized functionality pruned from its design, with a non-pruned EV5-like in-order Checker core. Our results show that by removing 3% of infrequently used functionality from the optimistic core an increase in frequency of 25% can be realized. Taking into account the replay overhead triggered by the removed functionality, the Tandem system is still able to achieve a 12% overall speedup.

The modeling of power and thermal behavior of processors requires challenging validation processes, which may be complex and undependable. In order to ameliorate some of the difficulties associated with the validation of power and thermal models, this paper describes an infrared measurement setup that simultaneously captures run-time power consumption, thermal characteristics, and performance activity counters from modern processors. We use infrared cameras with high spatial resolution (10x10µm) and high frame rate (125Hz) to capture thermal maps. Power measurements are obtained with a multimeter, while performance counters are obtained after modifying the operating system (Linux), both at a sampling rate of 1KHz. The synchronized traces can then be used in the validation process of possible thermal, power, and processor activity models.

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Temperature is a dominant factor in the performance, reliability, and leakage power consumption of modern processors. As a result, increasing numbers of researchers evaluate thermal characteristics in their proposals. In this paper, we measure a real processor focusing on its thermal characterization executing diverse workloads.Our results show that in real designs, thermal transients operate at larger scales than their performance and power counterparts. Conventional thermal simulation methodologies based on profilebased simulation or statistical sampling, such as Simpoint, tend to explore very limited execution spans. Short simulation times can lead to reduced matchings between performance and thermal phases. To illustrate these issues we characterize and classify from a thermal standpoint SPEC00 and SPEC06 applications, which are traditionally used in the evaluation of architectural proposals. This paper concludes with a list of recommendations regarding thermal modeling considerations based on our experimental insights.