go to top scroll for more


Projects: Projects for Investigator
Reference Number EP/V028154/1
Title C6: Correct-by-Construction Heterogeneous Coherence
Status Started
Energy Categories Energy Efficiency(Other) 5%;
Not Energy Related 95%;
Research Types Basic and strategic applied research 100%
Science and Technology Fields PHYSICAL SCIENCES AND MATHEMATICS (Computer Science and Informatics) 35%;
ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering) 65%;
UKERC Cross Cutting Characterisation Not Cross-cutting 100%
Principal Investigator Dr A Barbalace

Sch of Informatics
University of Edinburgh
Award Type Standard
Funding Source EPSRC
Start Date 15 November 2021
End Date 14 November 2025
Duration 48 months
Total Grant Value £494,698
Industrial Sectors Electronics
Region Scotland
Programme NC : ICT
Investigators Principal Investigator Dr A Barbalace , Sch of Informatics, University of Edinburgh (99.999%)
  Other Investigator Dr TC Grosser , Sch of Informatics, University of Edinburgh (0.001%)
  Industrial Collaborator Project Contact , University of St Andrews (0.000%)
Project Contact , Huawei Technologies (UK) Co. Ltd (0.000%)
Project Contact , Duke University (0.000%)
Web Site
Abstract About 55 years ago, Gordon Moore speculated that transistors will become smaller and more energy efficient every year. Since then, we have enjoyed exponentially increasing computer performance owing to what has been called the Moore's law.However, Moore's law is coming to an end and has already begun to disrupt the semiconductor industry. Absent the exponential performance and energy gains due to device scaling, industry has pivoted to hardware specialisation: targeting hardware to a specific computation class generally leads to orders of magnitude improvement in energy and performance.We are well and truly in the age of heterogeneous computing. A modern smartphone today has dozens of devices within a single chip, including CPUs, GPUs, and other accelerators. But efficiency hinges on reducing data movement between these devices; otherwise, it can seriously jeopardise the benefits of heterogeneous computing. Sadly, an analysis of Google workloads on a mobile device reveals that, on average, more than 60% of the overall energy is spent on moving around data.One promising approach to reducing data movement is called cache coherence. The cache coherence protocol, which automatically replicates data consistently, enables data to be accessed locally when it is safe to do so. Thus, it not only minimises data movement but it also does so in a programmer-transparent fashion.However, cache coherence protocols are notoriously hard to design and verify even for homogeneous multicores, where they have been deployed today. To make matters worse, we do not know how to keep the devices of a heterogeneous computer coherent correctly, in part because we do not yet understand what it means to be correct.In this project, we propose an entirely new way of designing coherence protocols. Instead of manually designing them and verifying them later, we propose an automatic method to generate them correctly. Our method is based on a new foundation of heterogeneous coherence called compound consistency models, which formally answers the question of how distinct coherence protocols should compose. If successful, the project will not only lift the major roadblock to efficient heterogeneous computing (data movements costs), it will also catalyse the burgeoning open hardware movement by democratising one of its trickiest components: cache coherence protocols
Publications (none)
Final Report (none)
Added to Database 11/01/22