2003 Fiscal Year Final Research Report Summary
A Study on Real-Time Garbage Collection under Multi-threaded Environment
| Project/Area Number |
13680389
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
計算機科学
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| Research Institution | University of Tsukuba |
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Principal Investigator |
MAEDA Atusi University of Tsukuba, Institute of Information Science and Electronics, Associate Professor, 電子・情報工学系, 助教授 (50293139)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Yoshinori University of Tsukuba, Institute of Information Science and Electronics, Professor, 電子・情報工学系, 教授 (00312827)
MATSUI Shogo Kanagawa University, Faculty of Science, Associate Professor, 理学部, 助教授 (00221581)
TANAKA Yoshio National Institute of Advanced Industrial Science and Technology, Grid Technology Research Center, Grid Infraware Team Leader, グリッド研究センター, 基盤ソフトチーム長 (10357460)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Garbage Collection / Real-Time Processing / Threads / Memory Allocation / Java |
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| Research Abstract |
On developing GC algorithm applicable to multi-threaded, hard real-time environment, we tried two different approaches. The first approach is to make incremental mark-sweep algorithm real-time. We improved the garbage collector of jexc, a Java language implementation, so that search time of free-list for allocation be performed in bounded time, with price of possible increase of fragmentation. But fragmentation will not be a problem in practical application. We chose Snapshot-at-the-Beginning algorithm as incremental garbage collector with Return Barrier, As a result, pause time is bounded even when stack level gets increased, and achieved real-time requirement in single-threaded applications. The second approach is to combine generational garbage collector and incremental garbage collector. This novel algorithm performs major collection incrementally every time minor collection is invoked, effectively removing long pause time caused by major collection. Using this approach, we implemented and evaluated coarse-grained incremental garbage collector which is a combination of copy-based generational collector and Treadmill-based incremental collector. The result was presented in IPSJ 45th SIGPRO.Experiments show that the garbage collector achieves high CPU efficiency, with pause time acceptable for many applications, although the algorithm is not hard real-time.
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