Copying Garbage Collection for the WAM: To Mark or Not to Mark?

Demoen, Bart; Nguyen, Phuong-Lan; Vandeginste, Ruben

doi:10.1007/3-540-45619-8_14

Cited by 4 publications

(6 citation statements)

References 12 publications

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“…The heap scanning for symbols is, in our case, proportional to the total size of the heaps of all engines, (possibly after running the heap GC as well in some). With this in mind, a copying heap GC algorithm [7,8,26] is likely to provide also better symbol GC performance for programs with highly volatile heap data. The impact of such algorithms on integration with symbol GC remains to be studied.…”

Section: Related Workmentioning

confidence: 98%

Integrated symbol table, engine and heap memory management in multi-engine prolog

Tarau

2011

Proceedings of the International Symposium on Memory Management

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We describe an integrated solution to symbol, heap and logic engine memory management in a context where exchanges of arbitrary Prolog terms occur between multiple dynamically created engines, implemented in a new Java-based experimental Prolog system.As our symbols represent not just Prolog atoms, but also handles to Java objects (including arbitrary size integers and decimals), everything is centered around a symbol garbage collection algorithm ensuring that external objects are shared and exchanged between logic engines efficiently.Taking advantage of a tag-on-data heap representation of Prolog terms, our algorithm performs in-place updates of live symbol references directly on heap cells.With appropriate fine tuning of collection policies our algorithm provides an integrated memory management solution for Prolog systems, with amortized cost dominated by normally occurring heap garbage collection costs.

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Section: Related Workmentioning

confidence: 98%

Integrated symbol table, engine and heap memory management in multi-engine prolog

Tarau

2011

Proceedings of the International Symposium on Memory Management

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“…Still, the marking phase adds a considerable cost to the copying algorithm and recently, work has been done to make copying without marking safer. Demoen et al (2002) show that double copying occurs rarely, and that a small change to the copying algorithm prevents multiple copying completely without marking (i.e., a list cell is never copied more than twice). In addition, an even simpler change is presented, which prevents multiple copying in a very common case.…”

Section: Introductionmentioning

confidence: 99%

“…We also assume basic knowledge about garbage collection in general; a good overview is given elsewhere (Wilson 1992;Jones and Lins 1996). Garbage collection for Prolog is discussed widely (Bruynooghe 1984;Appleby et al 1988;Bekkers et al 1992;Bevemyr and Lindgren 1994;Demoen et al 2002).…”

Section: Introductionmentioning

confidence: 99%

“…environment slots never contain an free variable). hProlog 1.7 uses by default optimistic copying (Demoen et al 2002) for garbage collection. We will refer to the systems with the incremental collector as inc gc and gen gc, and to the original system with the optimistic collector as opt gc.…”

Section: Introductionmentioning

confidence: 99%

“…chess is a slightly modified version of a program used in Castro and Costa (2001). This version was used before in Demoen et al (2002). mqueens was also used in Demoen et al (2002).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Incremental copying garbage collection for WAM-based Prolog systems

Vandeginste¹,

Demoen²

2007

Theory and Practice of Logic Programming

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The design and implementation of an incremental copying heap garbage collector for WAM-based Prolog systems is presented. Its heap layout consists of a number of equalsized blocks. Other changes to the standard WAM allow these blocks to be garbage collected independently. The independent collection of heap blocks forms the basis of an incremental collecting algorithm which employs copying without marking (contrary to the more frequently used mark© or mark&slide algorithms in the context of Prolog). Compared to standard semi-space copying collectors, this approach to heap garbage collection lowers in many cases the memory usage and reduces pause times. The algorithm also allows for a wide variety of garbage collection policies including generational ones. The algorithm is implemented and evaluated in the context of hProlog.

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Integrated symbol table, engine and heap memory management in multi-engine prolog

Tarau

2011

SIGPLAN Not.

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We describe an integrated solution to symbol, heap and logic engine memory management in a context where exchanges of arbitrary Prolog terms occur between multiple dynamically created engines, implemented in a new Java-based experimental Prolog system. As our symbols represent not just Prolog atoms, but also handles to Java objects (including arbitrary size integers and decimals), everything is centered around a symbol garbage collection algorithm ensuring that external objects are shared and exchanged between logic engines efficiently. Taking advantage of a tag-on-data heap representation of Prolog terms, our algorithm performs in-place updates of live symbol references directly on heap cells. With appropriate fine tuning of collection policies our algorithm provides an integrated memory management solution for Prolog systems, with amortized cost dominated by normally occurring heap garbage collection costs.

show abstract

Copying Garbage Collection for the WAM: To Mark or Not to Mark?

Cited by 4 publications

References 12 publications

Integrated symbol table, engine and heap memory management in multi-engine prolog

Integrated symbol table, engine and heap memory management in multi-engine prolog

Incremental copying garbage collection for WAM-based Prolog systems

Integrated symbol table, engine and heap memory management in multi-engine prolog

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