Description du projet
Extension du protocole de cohérence pour optimiser l’efficacité énergétique des processeurs multicœurs
Les processeurs multicœurs des dispositifs numériques comme les smartphones et les serveurs haute performance exigent une puissance de calcul accrue pour accéder aux nouvelles applications. Leurs performances peuvent cependant être grandement entravées par les techniques de spéculation au niveau matériel, qui exécutent souvent des opérations inutiles augmentant la consommation d’énergie de manière excessive. Il est dès lors essentiel de concevoir des processeurs multicœurs plus efficaces sur le plan énergétique. Le projet ECHO, financé par l’UE, vise à améliorer les performances et l’efficacité des futurs processeurs multicœurs en renforçant le rôle du protocole de cohérence de cache. L’ajout de simples extensions au protocole de cohérence de cache permet la réduction des instructions spéculées à tort dans le noyau de traitement et l’optimisation spéculative lors de la compilation.
Objectif
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.
Champ scientifique
Mots‑clés
Programme(s)
Régime de financement
ERC-COG - Consolidator GrantInstitution d’accueil
30003 Murcia
Espagne