Parallel break construct, or how to kill an activity tree

Yair I. Friedman*, Dror G. Feitelson, Iaakov Exman

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


Most parallel languages provide means to express parallelism, e.g. a parallel-do construct, but no means to terminate the parallel activities spawned by such constructs. We propose three high-level primitives for this purpose, which are defined by analogies with primitives that break out of sequential iterative constructs. The primitives are pcontinue, which terminates the calling activity, pbreak, which terminates all the activities in the construct that spawned the calling activity, and return, which terminates all the activities created in the current function call. These constructs are especially useful in search problems, where an activity that finds a solution can terminate other activities that are investigating inferior approaches. Given that parallel constructs can be nested, activities form a tree rooted at the original activity that started the program. The main challenge in implementing pbreak and return is identifying the subtree of activities that should be killed. Three algorithms were designed and implemented, and experiments show that using these constructs can provide significant performance benefits.

Original languageAmerican English
Pages (from-to)230-234
Number of pages5
JournalIEEE Symposium on Parallel and Distributed Processing - Proceedings
StatePublished - 1996
EventProceedings of the 1996 10th International Parallel Processing Symposium - Honolulu, HI, USA
Duration: 15 Apr 199619 Apr 1996


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