DocumentCode :
2536059
Title :
Handling Conflicts with Compiler´s Help in Software Transactional Memory Systems
Author :
Mannarswamy, Sandya ; Govindarajan, R.
Author_Institution :
Indian Inst. of Sci. & HP India, Bangalore, India
fYear :
2010
fDate :
13-16 Sept. 2010
Firstpage :
482
Lastpage :
491
Abstract :
Atomic sections are supported in software through the use of optimistic concurrency by using Software Transactional Memory (STM). However STM implementations incur high overheads which reduce the wide-spread use of this approach by programmers. Conflicts are a major source of overheads in STMs. The basic performance premise of a transactional memory system is the optimistic concurrency principle wherein data updates executed by the transactions are to disjoint objects/memory locations, referred to as Disjoint Access Parallel (DAP). Otherwise, the updates conflict, and all but one of the transactions are aborted. Such aborts result in wasted work and performance degradation. While contention management systems in STM implementations try to reduce conflicts by various runtime feedback control mechanisms, they are not aware of the application´s structure and data access patterns and hence typically act after the conflicts have occurred. In this paper we propose a scheme based on compiler analysis, which can identify static atomic sections whose instances, when executed concurrently by more than one thread always conflict. Such an atomic section is referred to as Always Conflicting Atomic Section (ACAS). We propose and evaluate two techniques Selective Pessimistic Concurrency Control (SPCC) and compiler inserted Early Conflict Checks (ECC) which can help reduce the STM overheads caused by ACAS. We show that these techniques help reduce the aborts in 4 of the STAMP benchmarks by up to 27.52% while improving performance by 1.24% to 19.31%.
Keywords :
concurrency control; data handling; program compilers; shared memory systems; transaction processing; always conflicting atomic section; atomic section; compiler analysis; contention management systems; data access patterns; disjoint access parallel; early conflict checks; feedback control mechanisms; handling conflict; optimistic concurrency; optimistic concurrency principle; selective pessimistic concurrency control; software transactional memory system; static atomic sections; Benchmark testing; Concurrency control; Concurrent computing; Parallel processing; Programming; Runtime; Software;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Parallel Processing (ICPP), 2010 39th International Conference on
Conference_Location :
San Diego, CA
ISSN :
0190-3918
Print_ISBN :
978-1-4244-7913-9
Electronic_ISBN :
0190-3918
Type :
conf
DOI :
10.1109/ICPP.2010.56
Filename :
5599190
Link To Document :
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