Per-Core Power Modeling for Heterogenous SoCs

Ganapati Bhat,Umit Y Ogras,Sumit K Mandal,Ayushi Agarwal,Jun Wang,Sai V Vadlamudi,Sai T Manchukonda

doi:10.3390/electronics10192428

Abstract

State-of-the-art mobile platforms, such as smartphones and tablets, are powered by heterogeneous system-on-chips (SoCs). These SoCs are composed of many processing elements, including multiple CPU core clusters (e.g., big.LITTLE cores), graphics processing units (GPUs), memory controllers and other on-chip resources. On the one hand, mobile platforms need to provide a swift response time for interactive apps and high throughput for graphics-oriented workloads; on the other hand, the power consumption must be under tight control to prevent high skin temperatures and energy consumption. Therefore, commercial systems feature a range of mechanisms for dynamic power and temperature control. However, these techniques rely on simple indicators, such as core utilization and total power consumption. System architects are typically limited to the total power consumption, since multiple resources share the same power rail. More importantly, most of the power rails are not exposed to the input/output pins. To address this challenge, this paper presents a thorough methodology to model the power consumption of major resources in heterogeneous SoCs. The proposed models utilize a wide range of performance counters to capture the workload dynamics accurately. Experimental validation on a Nexus 6P phone, powered by an octa-core Snapdragon 810 SoC, showed that the proposed models can estimate the power consumption within a 10% error margin.

Highlights

Mobile platforms have become ubiquitous due to their crucial role in enabling everyday tasks, such as messaging, calling, gaming, navigation, and web browsing [1]
This paper proposes a per-core-power modeling methodology and its application to the Snapdragon 810 Heterogeneous SoC
The power models were developed by measuring the power consumption and collecting performance data, while running representative benchmarks at varying temperatures and operating frequencies

Summary

Introduction

Mobile platforms have become ubiquitous due to their crucial role in enabling everyday tasks, such as messaging, calling, gaming, navigation, and web browsing [1] This success is primarily due to heterogeneous SoCs, which provide competitive performance in a mobile form factor [2,3]. Graphics processing units (GPUs), display processing engines, and audio processors, have become standard components of state-of-the-art SoCs [2,7,8,9]. Any specialized function, such as display rendering, is performed in the corresponding PE, achieving higher performance and lower power consumption than a general-purpose core. Both the overall system energy efficiency and the power consumption are improved significantly compared to a system that consists of only CPU cores

Methods

Results

Conclusion