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Towards variability-aware frequency scaling on heterogeneous edge platforms Abdelhafez, Hazem A.

Abstract

Recent Edge applications (e.g., machine learning inference) are becoming more sophisticated and computationally demanding. To meet their Quality of Service (QoS) objectives, today’s heterogeneous Edge platforms (e.g., NVIDIA Jetson platform) incorporate several architectural innovations. One that stands out is the wide frequency configuration space (more than a dozen frequency levels per processing unit spanning a 10x max-min ratio). We postulate that this can be harnessed to better navigate the trade-off space between performance and power consumption. This dissertation makes progress towards harnessing frequency scaling on Edge platforms. We start by exploring the potential gains from frequency scaling on the NVIDIA Jetson platform. To this end, we develop an empirical methodology to characterize the performance and power consumption behavior of the Jetson platform under different frequency configurations. Our characterization indicates that indeed there is an opportunity to improve performance and/or energy-efficiency with careful frequency configuration selection. However, one challenge is to estimate the impact of the frequency configuration choice on performance and power consumption of the workload. To overcome this challenge, we employ machine learning techniques to build performance and power consumption models for the target workload. While developing these models, we find that the quality of their predictions depends on where the models are deployed (even if they are deployed on identical devices with identical software stacks). This leads us to postulate that variability in performance and power consumption among nominally identical Edge platforms exists and is sizeable. To investigate this hypothesis, we develop statistical tools that allow developers to detect, quantify, categorize, and compare variability. Then we present a set of actions one can take to mitigate the impact of variability. We evaluate all the techniques and approaches on two clusters of popular Edge platforms - the Jetson AGX and Nano. Finally, we focus on developing variability-aware performance and power consumption models. We show that not accounting for variability can severely impact the quality of predictions. The evaluation of the models shows that accounting for inter-node variability improves the Root Mean Square Error (RMSE) by 9.5% and 31.9% for runtime and power models respectively.

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Attribution-NonCommercial-NoDerivatives 4.0 International