Project description
Extending the coherence protocol to optimise multicore processors' energy efficiency
Multicore processors in digital devices such as smartphones and high-performance servers require increased computational power to access emerging applications. However, their performance can be significantly impeded by speculation techniques in hardware, which often perform unnecessary operations that excessively increase power consumption. Therefore, it is essential to design multicore processors that are more energy efficient. The EU-funded ECHO project aims to improve the performance and efficiency of future multicore processors by enhancing the role of the cache coherence protocol. By adding simple extensions to the cache coherence protocol, it will be possible to reduce misspeculations at the processing core and enable speculative optimisation during compilation.
Objective
Multicore processors are present nowadays in most digital devices, from smartphones to high-performance
servers. The increasing computational power of these processors is essential for enabling many important
emerging application domains such as big-data, media, medical, or scientific modeling. A fundamental
technique to improve performance is speculation, a technique that consists in executing work before it is
known if it is actually needed. In hardware, speculation significantly increases energy consumption by
performing unnecessary operations, while speculation in software (e.g. compilers) is not the default thus
preventing performance optimizations. Since performance in current multicores is limited by their power
budget, it is imperative to make multicores as energy-efficient as possible to increase performance even
further.
In a multicore architecture, the cache coherence protocol is an essential component since its unique but
challenging role is to offer a simple and unified view of the memory hierarchy. This project envisions that
extending the role of the coherence protocol to simplify other system components will be the key to
overcome the performance and energy limitations of current multicores. In particular, ECHO proposes to
add simple but effective extensions to the cache coherence protocol in order to (i) reduce and even
eliminate misspeculations at the processing cores and synchronization mechanisms and to (ii) enable
speculative optimizations at compile time. The goal of this innovative approach is to improve the
performance and energy efficiency of future multicore architectures. To accomplish the objectives
proposed in this project, I will build on my 14 years expertise in cache coherence, documented in over 40
publications of high impact.
Fields of science
Keywords
Programme(s)
Funding Scheme
ERC-COG - Consolidator GrantHost institution
30003 Murcia
Spain