NDLI: An efficient algorithm for the run-time parallelization of DOACROSS loops

Content Provider	ACM Digital Library
Author	Torrellas, Josep Chen, Ding Kai Yew, Pen Chung
Abstract	While automatic parallelization of loops usually relies on compile-time analysis of data dependences, for some loops the data dependences cannot be determined at compile time. An example is loops accessing arrays with subscripted subscripts. To parallelize these loops, it is necessary to perform run-time analysis. In this paper, we present a new algorithm to parallelize these loops at run time. Our scheme handles any type of data dependence in the loop without requiring any special architectural support in the multiprocessor. Furthermore, compared to an older scheme with the same generality, our scheme significantly reduces the amount of processor communication required and increases the overlap among dependent iterations. We evaluate our algorithm with parameterized loops running on the 32-processor Cedar shared-memory multiprocessor. The results show speedups over the serial code of up to 14 with the full overhead of run-time analysis and of up to 27 if part of the analysis is reused across loop invocations. Moreover, the algorithm outperforms the older scheme in nearly all cases, reaching speedups of up to times when the loop has many dependences.
Starting Page	518
Ending Page	527
Page Count	10
File Format	PDF
ISBN	0818666056
ISSN	10639535
Language	English
Publisher	Association for Computing Machinery (ACM)
Publisher Date	1994-11-14
Access Restriction	Subscribed
Content Type	Text
Resource Type	Article

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

An efficient algorithm for the run-time parallelization of DOACROSS loops