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Title: CilkSpec: Optimistic Concurrency for Cilk

Recursive parallel programming models such as Cilk strive to simplify the task of parallel programming by enabling a simple divide-and-conquer model of programming. This model is effective in re- cursively partitioning work into smaller parts and combining their results. However, recursive work partitioning can impose additional constraints on concurrency than is implied by the true dependences in a program. In this paper, we present a speculation-based approach to alleviate the concurrency constraints imposed by such recursive parallel programs. We design a runtime infrastructure that supports speculative execution and a predictor to accurately learn and identify opportunities to relax extraneous concurrency constraints. Experimental evaluation demonstrates that speculative relaxation of concurrency constraints can deliver gains of up to 1.6× on 30 cores over baseline Cilk.
Authors:
; ;
Publication Date:
OSTI Identifier:
1236312
Report Number(s):
PNNL-SA-111827
KJ0402000
DOE Contract Number:
AC05-76RL01830
Resource Type:
Conference
Resource Relation:
Conference: Supercomputing (SC15): Proceedings of the International Conference for High Performance Computing, Networking, Storage and Analysis, November 15-20, 2015, Austin, Texas, Paper No. 83
Publisher:
Association for Computing Machinery (ACM), New York, NY, United States(US).
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
fork-join; cilk; speculation; optimistic concurrency