Global Data Re-allocation via Communication Aggregation in Chapel

Conference · Mon Oct 01 04:00:00 EDT 2012 · 2012 IEEE 24th International Symposium on Computer Architecture and High Performance Computing; 24-26 Oct. 2012; New York, NY, USA

DOI:https://doi.org/10.1109/SBAC-PAD.2012.18· OSTI ID:1567594

Sanz, Alberto; Asenjo, Rafael; Lopez, Juan; Larrosa, Rafael; Navarro, Angeles; Litvinov, Vassily; Choi, Sung-Eun; Chamberlain, Bradford L.

Chapel is a parallel programming language designed to improve the productivity and ease of use of conventional and parallel computers. This language currently delivers sub optimal performance when executing codes that perform global data re-allocation operations on distributed memory architectures. This is mainly due to data communication that is done without aggregation (one message for each remote array element). In this work, we analyze Chapel's standard Block and Cyclic distribution modules and optimize the communication routines for array assignments by performing aggregation. Thanks to the expressive power of Chapel, the compiler and runtime have enough information to do communication aggregation without user intervention. The runtime relies on the low-level GAS Net networking layer, whose versions of one-sided bulk put/get routines that support strides are particularly useful for us. Experimental results conducted on Hector (a Cray XE6) and Jaguar (Cray XK6)reveal that the implemented techniques can lead to significant reductions in communication time.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
• Sponsoring Organization: USDOE Office of Science; USDOE
• OSTI ID: 1567594
• Conference Information: Journal Name: 2012 IEEE 24th International Symposium on Computer Architecture and High Performance Computing; 24-26 Oct. 2012; New York, NY, USA
• Country of Publication: United States
• Language: English