Work

ProtoGen: Automatically Generating Directory Cache Coherence Protocols from Atomic Specifications

Year: 2018

Type: conference-paper

Abstract: Designing directory cache coherence protocols is complicated because coherence transactions are not atomic in modern multicore processors. A coherence transaction comprises multiple messages, and these messages can interleave with other conflicting coherence transactions initiated by other cores. To overcome this architectural challenge, we present ProtoGen, an automated tool for taking the description of a directory protocol with atomic transactions (i.e., no concurrency) and generating the corresponding protocol for a multicore with non-atomic transactions. ProtoGen outputs the finite state machines for the cache and directory controllers, including all of the transient states that are possible with concurrent transactions. We have used ProtoGen to generate complete MSI, MESI, and MOSI protocols given their stable state protocol specifications. We have verified the generated protocols for safety and deadlock freedom using the Murφ model checker. Our generated protocols are identical to or better than manually generated protocols, at times even discovering opportunities to reduce stalling.

Source: Proceedings - International Symposium on Computer Architecture/Proceedings

DOI: 10.1109/isca.2018.00030

Authors: Nicolai Oswald, Vijay Nagarajan, Daniel J. Sorin

Institution: University of Edinburgh

Language: English

Topic: Parallel Computing and Optimization Techniques

Subfield: Hardware and Architecture

Field: Computer Science

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Leverhulme Trust, Royal Academy of Engineering, Engineering and Physical Sciences Research Council

Awards: G2316399547, EPSRC Centre for Doctoral Training in Pervasive Parallelism, C3: Scalable & Verified Shared Memory via Consistency-directed Cache Coherence, G5709231062