Section: New Results

Co-scheduling Amdahl applications on cache-partitioned systems

Participants : Guillaume Aupy [Inria Tadaam] , Anne Benoit, Sicheng Dai [East China Normal University, China] , Loïc Pottier, Padma Raghavan [Vanderbilt University, Nashville TN, USA] , Yves Robert, Manu Shantharam [San Diego Supercomputer Center, San Diego CA, USA] .

Cache-partitioned architectures allow subsections of the shared last-level cache (LLC) to be exclusively reserved for some applications. This technique dramatically limits interactions between applications that are concurrently executing on a multi-core machine. Consider $n$ applications that execute concurrently, with the objective to minimize the makespan, defined as the maximum completion time of the $n$ applications. Key scheduling questions are: (i) which proportion of cache and (ii) how many processors should be given to each application? In this work, we provide answers to (i) and (ii) for Amdahl applications. Even though the problem is shown to be NP-complete, we give key elements to determine the subset of applications that should share the LLC (while remaining ones only use their smaller private cache). Building upon these results, we design efficient heuristics for Amdahl applications. Extensive simulations demonstrate the usefulness of co-scheduling when our efficient cache partitioning strategies are deployed.

This work is available as a research report and has been accepted for publication in the IJHPCA journal.