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Author Lu, Shan ♦ Volos, Haris ♦ Tack, Andres Jaan ♦ Swift, Michael M.
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
File Format PDF
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Computer programming, programs & data
Subject Keyword Concurrency bug ♦ Deadlock ♦ Atomicity violation ♦ Concurrent program ♦ Debugging ♦ Transactional memory
Abstract Multithreaded programs often suffer from synchronization bugs such as atomicity violations and deadlocks. These bugs arise from complicated locking strategies and ad hoc synchronization methods to avoid the use of locks. A survey of the bug databases of major open-source applications shows that concurrency bugs often take multiple fix attempts, and that fixes often introduce yet more concurrency bugs. Transactional memory (TM) enables programmers to declare regions of code atomic without specifying a lock and has the potential to avoid these bugs. Where most previous studies have focused on using TM to write new programs from scratch, we consider its utility in fixing existing programs with concurrency bugs. We therefore investigate four methods of using TM on three concurrent programs. Overall, we find that 29% of the bugs are not fixable by transactional memory, showing that TM does not address many important types of concurrency bugs. In particular, TM works poorly with extremely long critical sections and with deadlocks involving both condition variables and I/O. Conversely, we find that for 56% of the bugs, transactional memory offers demonstrable value by simplifying the reasoning behind a fix or the effort to implement a fix, and using transactions in the first place would have avoided 71% of the bugs examined. We also find that ad hoc synchronization put in place to avoid the overhead of locking can be greatly simplified with TM, but requires hardware support to perform well.
Description Affiliation: University of Wisconsin-Madison, Madison, WI, USA (Volos, Haris; Swift, Michael M.; Lu, Shan) || Skype Limited, Tallinn, Estonia (Tack, Andres Jaan)
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 1983-05-01
Publisher Place New York
Journal ACM SIGPLAN Notices (SIGP)
Volume Number 47
Issue Number 4
Page Count 12
Starting Page 211
Ending Page 222

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Source: ACM Digital Library