COKE

Software-controlled consistency and coherence for many-core processor architectures

(Third Party Funds Single)

Project leader: Wolfgang Schröder-Preikschat
Project members: Gabor Drescher, Stefan Reif, Timo Hönig
Start date: 1. September 2012
End date: 31. March 2021
Acronym: COKE
Funding source: DFG-Einzelförderung / Sachbeihilfe (EIN-SBH)

Abstract:

The achievable computing capacity of individual processors currently strikes at its technological boundary line. Further improvement in performance is attainable only by the use of many computation cores. While processor architectures of up to 16 cores mark the topical state of the art in commercially available products, here and there systems of 100 computing cores are already obtainable. Architectures exceeding thousand computation cores are to be expected in the future. For better scalability, extremely powerful communication networks are integrated in these processors (network on chip, NoC), so that they combine de facto properties of a distributed system with those of a NUMA system. The extremely low latency and high bandwidth of those networks opens up the possibility to migrate methods of replication and consistency preservation from hardware into operating and run-time systems and, thus, to flexibly counteract notorious problems such as false sharing of memory cells, cache-line thrashing, and bottlenecks in memory bandwidth.

Therefore, the goal of the project is to firstly design a minimal, event-driven consistency kernel (COKE) for such many-core processors that provides the relevant elementary operations for software-controlled consistency preservation protocols for higher levels. On the basis of this kernel, diverse "consistency machines" will be designed, which facilitate different memory semantics for software- and page-based shared memory.