Architectural Clock Gating and Way-Based Shutdown Techniques for System-Level Cache
Author(s): Karthik Wali
Publication #: 2507007
Date of Publication: 12.03.2023
Country: United States
Pages: 1-9
Published In: Volume 9 Issue 2 March-2023
DOI: https://doi.org/10.5281/zenodo.16500588
Abstract
System-level caches are a vital component of modern microprocessor architectures, providing a buffer between the fast central processing unit (CPU) and slower main memory. These caches reduce memory access latency and improve overall system performance. However, their increasing size and complexity have led to substantial power consumption, posing challenges for energy efficiency—particularly in mobile devices, data centers, and embedded systems. Power dissipation in caches can be broadly classified into dynamic power, caused by switching activities, and static or leakage power, which results from current leakage in transistors even when they are idle.
Architectural clock gating (ACG) and way-based shutdown (WBS) are two advanced low-power techniques aimed at mitigating this issue. ACG addresses dynamic power by selectively disabling the clock signal to parts of the cache that are not actively engaged in operations. This prevents unnecessary circuit activity, conserving energy. In contrast, WBS targets leakage power by turning off unused cache ways, thereby reducing the standby power consumed by idle sections of the cache. Together, these techniques represent a hybrid strategy that balances performance and power efficiency.
This paper presents a comprehensive analysis of ACG and WBS methods, exploring their individual and combined effectiveness in reducing power consumption in system-level caches. Through an extensive review of recent literature, we identify various implementation approaches and evaluate their design trade-offs, including area overhead, latency, and performance impact. We also introduce a simulation-based methodology using industry-standard benchmarks such as SPEC CPU and PARSEC to empirically evaluate the impact of ACG and WBS on cache energy consumption and system performance.
The experimental results indicate that ACG and WBS, when employed in tandem, can achieve significant power savings—up to 35% reduction in cache energy usage—while maintaining acceptable levels of performance degradation. The findings underscore the potential of combining dynamic and static power management strategies in cache design to meet the dual objectives of high performance and low energy consumption. These techniques are especially relevant for applications requiring extended battery life or reduced operational costs, such as smartphones, Internet of Things (IoT) devices, and large-scale server farms.
ACG and WBS provide viable, complementary solutions for addressing the power challenges in modern cache architectures. Their integration into existing and future processor designs could play a crucial role in enabling energy-efficient computing across diverse platforms. This paper aims to contribute to the growing body of knowledge on low-power cache design and encourage further innovation in this important area.
Keywords: Architectural clock gating, way-based shutdown, system-level cache, power optimization, dynamic power, leakage power, cache memory, low-power design, energy-efficient computing, cache management
Download/View Count: 152
Share this Article