Power is a primary objective in modern processor design, requiring accurate yet efficient power modeling techniques. Architecture-level power models are necessary for early power optimization and design space exploration. However, classical analytical architecture-level power models (e.g., McPAT) suffer from significant inaccuracies. Emerging machine learning (ML)-based power models, despite their superior accuracy in research papers, are not widely adopted in the industry. In this work, we point out three inherent limitations of ML-based power models: unreliability, limited interpretability, and difficulty in usage. This work proposes a new analytical power modeling framework named ReadyPower, which is ready-for-use by being reliable, interpretable, and handy. We observe that the root cause of the low accuracy of classical analytical power models is the discrepancies between the real processor implementation and the processor's analytical model. To bridge the discrepancies, we introduce architecture-level, implementation-level, and technology-level parameters into the widely adopted McPAT analytical model to build ReadyPower. The parameters at three different levels are decided in different ways. In our experiment, averaged across different training scenarios, ReadyPower achieves >20% lower mean absolute percentage error (MAPE) and >0.2 higher correlation coefficient R compared with the ML-based baselines, on both BOOM and XiangShan CPU architectures.baselines, on both BOOM and XiangShan CPU architectures.
翻译:功耗是现代处理器设计的主要目标之一,需要精确且高效的功耗建模技术。架构级功耗模型对于早期功耗优化和设计空间探索至关重要。然而,经典的分析型架构级功耗模型(如McPAT)存在显著的不准确性。新兴的基于机器学习(ML)的功耗模型尽管在研究论文中展现出更高的准确性,但在工业界并未得到广泛应用。本文指出基于机器学习的功耗模型存在三个固有局限性:不可靠性、有限的可解释性以及使用困难。本研究提出了一种名为ReadyPower的新型分析型功耗建模框架,该框架具备可靠性、可解释性和易用性,可直接投入使用。我们观察到,经典分析型功耗模型精度低下的根本原因在于实际处理器实现与处理器分析模型之间的差异。为弥合这些差异,我们在广泛采用的McPAT分析模型中引入了架构级、实现级和技术级参数,从而构建了ReadyPower。这三个不同层级的参数通过不同方式确定。在我们的实验中,在不同训练场景下平均而言,ReadyPower在BOOM和香山CPU架构上,相较于基于机器学习的基线模型,实现了平均绝对百分比误差(MAPE)降低超过20%,相关系数R提高超过0.2。