WO2001031455A1 - A method for garbage collection of unused methods - Google Patents
A method for garbage collection of unused methods Download PDFInfo
- Publication number
- WO2001031455A1 WO2001031455A1 PCT/SE2000/002096 SE0002096W WO0131455A1 WO 2001031455 A1 WO2001031455 A1 WO 2001031455A1 SE 0002096 W SE0002096 W SE 0002096W WO 0131455 A1 WO0131455 A1 WO 0131455A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- methods
- program
- regenerated
- garbage collecting
- thread
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F12/00—Accessing, addressing or allocating within memory systems or architectures
- G06F12/02—Addressing or allocation; Relocation
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F12/00—Accessing, addressing or allocating within memory systems or architectures
- G06F12/02—Addressing or allocation; Relocation
- G06F12/0223—User address space allocation, e.g. contiguous or non contiguous base addressing
- G06F12/023—Free address space management
- G06F12/0253—Garbage collection, i.e. reclamation of unreferenced memory
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S707/00—Data processing: database and file management or data structures
- Y10S707/99951—File or database maintenance
- Y10S707/99956—File allocation
- Y10S707/99957—Garbage collection
Definitions
- the present invention relates to a method of improving the effectiveness of a data processing application.
- the invention is concerned with increasing the data processing rate in virtual machines, and then particularly with respect to the Java program language.
- the invention is not restricted to Java, but can be applied with many program languages, although the invention is described below primarily with reference to Java.
- the method is intended for use with adaptive optimisation of a program.
- adaptive optimisation the program is restructured and different parts of the program are optimised as the program is run.
- the general problem of increasing data processing capacity resides in the rapid creation of new memory sites, since the longer the program is run, the more memory space is required.
- Java and other dynamic program languages include an automatic memory management. This means that the programmer need not keep an account of those parts of the memory that are used.
- the virtual machine carries out a so-called garbage collection from time to time, meaning, in principle, that the virtual machine scans the entire memory and finds which objects have been stored in the memory and which the program can no longer address. These parts of the memory are returned for later use.
- Java also includes methods for so called thread management methods.
- Java incorporates a system for supporting or simulating the simultaneous processing of two or more programs.
- the thread management can be divided into two parts. One part concerns the manner in which different threads are structured in a controlled manner. Another part is concerned with which threads shall be run and which threads shall be passive and wait to be run. In order to further increase effectiveness and place occupied memory space at the disposal of the program, it is not sufficient to solely optimise the memory with respect to the objects.
- the present invention solves this problem.
- the present invention thus relates to a method of improving the effectiveness of a data processing application when using a virtual machine, where the program includes many methods, i.e. program sections, that are stored in the memory of the computer used, and where garbage collecting is used by said program, wherein the inventive method is characterised by a first step in which all so-called thread stacks are analysed with respect to methods required thereby; a second step in which each of the methods required is caused to be regenerated where occurrent references to a method are replaced with reference to regenerated methods prior to the regeneration of a method; and by a third step in which all non-regenerated methods are erased, wherein the corresponding memory space is placed at the disposal of said program.
- the inventive method is characterised by a first step in which all so-called thread stacks are analysed with respect to methods required thereby; a second step in which each of the methods required is caused to be regenerated where occurrent references to a method are replaced with reference to regenerated methods prior to the regeneration of a method; and by
- FIG. 1 is a block diagram
- FIG. 3 illustrates methods regenerated in accordance with the invention.
- Figure 1 shows that a Java virtual machine, JVM, can be used to run different data programs 1, 2, 3, regardless of whether the operative system is WinNT, LINUX, Solaris or some other system.
- Java is a very popular program language
- the present invention is not restricted to this language but can be applied to all object-orientated and platform-independent corresponding program languages.
- the present invention thus relates to a method of improving the effectiveness of a data processing application when using a virtual machine, wherein the program includes a large number of methods, i.e. program sections, that are stored in the memory of the computer used, and wherein a garbage collecting process is used by the program. It is previously known to garbage collect objects and therewith erase objects that are no longer in current use thereby placing corresponding memory capacity at disposal.
- all so called thread stacks are analysed with respect to the methods required, in a first step of the inventive method.
- each of the methods required is regenerated, where occurrent references to a method are replaced with references to regenerated methods prior to said regeneration.
- all non- regenerated methods are erased and the corresponding memory space placed at the disposal of the program.
- This procedure does not only clean-out unused methods, but also results in a reorganization between those methods that have been regenerated, so as to direct references of the methods immediately to a regenerated method instead of proceeding via an old method that is no longer used.
- Foo starts on the memory address 4711.
- Apa starts on the address 4714 and bar starts on the address 4720.
- Analysis of the thread stacks shows that only the methods foo and bar are used, and consequently foo and bar have not been referenced to the method apa.
- the method foo and bar are regenerated to those methods illustrated in Figure 3.
- the methods foo and bar are recreated precisely, although with the difference that the methods obtain new addresses and that then the foo reference to bar points to the new bar address 4903.
- Such a method can be used when applying the present invention.
- one thread is stopped at a time whilst the program is running, wherewith methods used for a stopped thread are transferred to a list and the thread then restarted. The methods in the list are then regenerated and stored. All threads are later caused to be stopped at the same time, subsequent to having treated all threads in this way, namely so that all used methods relating to the threads concerned have been regenerated. All methods that have not been regenerated are erased and all threads are restarted with the regenerated methods.
- This method obviates the need to stop running the program, since the regeneration takes place intermittently.
- lock mechanisms are used in Java and corresponding languages. Different lock mechanisms can be selected. The important thing is to select the lock mechanism that is the most effective in preventing more than one thread having access to a given object at the same time as another thread.
- a synchronisation problem exists when several threads desire access to one and the same object or source. In order to solve this problem in Java, each thread endeavours to reach the source lock.
- the source lock mechanism can be used in various ways. The effectiveness of different lock mechanisms will depend on how threads endeavour to obtain access to synchronised sources.
- the most effective locking mechanisms are identified in a step prior to said first step, and the methods that use a thus identified locking mechanism are regenerated.
- garbage collecting algorithms With respect to garbage collecting algorithms, these also need to be selected. Many object orientated languages use garbage collection. This means that the programmer need not instruct the system explicitly that a certain object is no longer required. The system is responsible for this detection, and reclaims the part of the memory occupied by the object.
- the allocation and length of life of the various objects are determined in a step prior to said first method step, whereafter the most effective garbage collecting algorithm is caused to be identified and the methods constituting the requisite garbage collecting algorithms are regenerated and remaining garbage collecting algorithms then erased.
- Application of the preferred embodiments provides a highly effective method for optimising codes, threads and memory management, where a generic feature resides in the identification and regeneration of methods so as to not load the system with unused methods.
Abstract
Description
Claims
Priority Applications (10)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA002389168A CA2389168C (en) | 1999-10-28 | 2000-10-27 | A method for garbage collection of unused methods |
AU15632/01A AU768181B2 (en) | 1999-10-28 | 2000-10-27 | A method for garbage collection of unused methods |
US10/111,566 US7194494B1 (en) | 1999-10-28 | 2000-10-27 | Method for garbage collection of unused methods |
KR1020027005468A KR20020070270A (en) | 1999-10-28 | 2000-10-27 | A method for garbage collection of unused methods |
DE60039628T DE60039628D1 (en) | 1999-10-28 | 2000-10-27 | METHOD FOR THE FREE STORAGE COLLECTION OF UNUSED PROCEDURES |
JP2001533523A JP4150518B2 (en) | 1999-10-28 | 2000-10-27 | Method for collecting unnecessary data for unused program sections |
EP00978146A EP1240589B1 (en) | 1999-10-28 | 2000-10-27 | A method for garbage collection of unused methods |
US10/162,308 US6970893B2 (en) | 2000-10-27 | 2002-06-04 | System and method for regeneration of methods and garbage collection of unused methods |
US11/187,529 US7650370B2 (en) | 1999-10-28 | 2005-07-22 | System and method for regeneration of methods and garbage collection of unused methods |
US11/586,192 US20070073794A1 (en) | 1999-10-28 | 2006-10-25 | Method for garbage collection of unused methods |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9903890-3 | 1999-10-28 | ||
SE9903890A SE514318C2 (en) | 1999-10-28 | 1999-10-28 | Process for streamlining a data processing process using a virtual machine and using a garbage collection procedure |
Related Child Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/111,566 A-371-Of-International US7194494B1 (en) | 1999-10-28 | 2000-10-27 | Method for garbage collection of unused methods |
US10/162,308 Continuation-In-Part US6970893B2 (en) | 1999-10-28 | 2002-06-04 | System and method for regeneration of methods and garbage collection of unused methods |
US11/586,192 Continuation US20070073794A1 (en) | 1999-10-28 | 2006-10-25 | Method for garbage collection of unused methods |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2001031455A1 true WO2001031455A1 (en) | 2001-05-03 |
Family
ID=20417516
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE2000/002096 WO2001031455A1 (en) | 1999-10-28 | 2000-10-27 | A method for garbage collection of unused methods |
Country Status (11)
Country | Link |
---|---|
US (2) | US7194494B1 (en) |
EP (1) | EP1240589B1 (en) |
JP (1) | JP4150518B2 (en) |
KR (1) | KR20020070270A (en) |
CN (1) | CN100382047C (en) |
AT (1) | ATE402443T1 (en) |
AU (1) | AU768181B2 (en) |
CA (1) | CA2389168C (en) |
DE (1) | DE60039628D1 (en) |
SE (1) | SE514318C2 (en) |
WO (1) | WO2001031455A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8010737B2 (en) | 2007-06-08 | 2011-08-30 | Robert Bosch Gmbh | Method and device for reorganizing data in a memory system, in particular for control devices in motor vehicles |
CN114265670A (en) * | 2022-03-02 | 2022-04-01 | 阿里云计算有限公司 | Memory block sorting method, medium and computing device |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2005018425A (en) * | 2003-06-26 | 2005-01-20 | Matsushita Electric Ind Co Ltd | Program conversion method, program and storage medium |
EP1659496B1 (en) * | 2003-06-30 | 2010-09-01 | Panasonic Corporation | Garbage collection system |
EP1622009A1 (en) * | 2004-07-27 | 2006-02-01 | Texas Instruments Incorporated | JSM architecture and systems |
CA2700217C (en) * | 2010-04-01 | 2011-07-19 | Ibm Canada Limited - Ibm Canada Limitee | Write barrier elision for reference arrays |
US10606614B2 (en) * | 2016-07-31 | 2020-03-31 | Oracle International Corporation | Container-based language runtime using a variable-sized container for an isolated method |
Citations (3)
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US5088036A (en) * | 1989-01-17 | 1992-02-11 | Digital Equipment Corporation | Real time, concurrent garbage collection system and method |
US5915255A (en) * | 1997-04-23 | 1999-06-22 | Sun Microsystems, Inc. | Method and apparatus for referencing nodes using links |
WO1999032978A1 (en) * | 1997-12-19 | 1999-07-01 | Microsoft Corporation | Incremental garbage collection |
Family Cites Families (9)
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US4797810A (en) * | 1986-06-26 | 1989-01-10 | Texas Instruments Incorporated | Incremental, multi-area, generational, copying garbage collector for use in a virtual address space |
US5293614A (en) * | 1991-04-08 | 1994-03-08 | Texas Instruments Incorporated | System and method for hard real-time garbage collection requiring a write barrier but no read barrier |
US5355483A (en) * | 1991-07-18 | 1994-10-11 | Next Computers | Asynchronous garbage collection |
CA2098459A1 (en) * | 1992-06-15 | 1993-12-16 | James L. Adcock | Computer method and system for conservative-stack and generational heap garbage collection |
US5692193A (en) * | 1994-03-31 | 1997-11-25 | Nec Research Institute, Inc. | Software architecture for control of highly parallel computer systems |
US6463581B1 (en) * | 1996-10-03 | 2002-10-08 | International Business Machines Corporation | Method for determining reachable methods in object-oriented applications that use class libraries |
US6041179A (en) * | 1996-10-03 | 2000-03-21 | International Business Machines Corporation | Object oriented dispatch optimization |
US5873105A (en) * | 1997-06-26 | 1999-02-16 | Sun Microsystems, Inc. | Bounded-pause time garbage collection system and method including write barrier associated with a source instance of a partially relocated object |
US6654951B1 (en) * | 1998-12-14 | 2003-11-25 | International Business Machines Corporation | Removal of unreachable methods in object-oriented applications based on program interface analysis |
-
1999
- 1999-10-28 SE SE9903890A patent/SE514318C2/en not_active IP Right Cessation
-
2000
- 2000-10-27 JP JP2001533523A patent/JP4150518B2/en not_active Expired - Lifetime
- 2000-10-27 WO PCT/SE2000/002096 patent/WO2001031455A1/en active IP Right Grant
- 2000-10-27 CA CA002389168A patent/CA2389168C/en not_active Expired - Lifetime
- 2000-10-27 AU AU15632/01A patent/AU768181B2/en not_active Expired
- 2000-10-27 EP EP00978146A patent/EP1240589B1/en not_active Expired - Lifetime
- 2000-10-27 US US10/111,566 patent/US7194494B1/en not_active Expired - Lifetime
- 2000-10-27 AT AT00978146T patent/ATE402443T1/en not_active IP Right Cessation
- 2000-10-27 DE DE60039628T patent/DE60039628D1/en not_active Expired - Lifetime
- 2000-10-27 KR KR1020027005468A patent/KR20020070270A/en active Search and Examination
- 2000-10-27 CN CNB008164169A patent/CN100382047C/en not_active Expired - Lifetime
-
2006
- 2006-10-25 US US11/586,192 patent/US20070073794A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5088036A (en) * | 1989-01-17 | 1992-02-11 | Digital Equipment Corporation | Real time, concurrent garbage collection system and method |
US5915255A (en) * | 1997-04-23 | 1999-06-22 | Sun Microsystems, Inc. | Method and apparatus for referencing nodes using links |
WO1999032978A1 (en) * | 1997-12-19 | 1999-07-01 | Microsoft Corporation | Incremental garbage collection |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8010737B2 (en) | 2007-06-08 | 2011-08-30 | Robert Bosch Gmbh | Method and device for reorganizing data in a memory system, in particular for control devices in motor vehicles |
CN114265670A (en) * | 2022-03-02 | 2022-04-01 | 阿里云计算有限公司 | Memory block sorting method, medium and computing device |
Also Published As
Publication number | Publication date |
---|---|
SE9903890D0 (en) | 1999-10-28 |
US7194494B1 (en) | 2007-03-20 |
US20070073794A1 (en) | 2007-03-29 |
ATE402443T1 (en) | 2008-08-15 |
EP1240589A1 (en) | 2002-09-18 |
JP4150518B2 (en) | 2008-09-17 |
AU1563201A (en) | 2001-05-08 |
CA2389168C (en) | 2009-10-06 |
KR20020070270A (en) | 2002-09-05 |
EP1240589B1 (en) | 2008-07-23 |
JP2003513356A (en) | 2003-04-08 |
SE9903890L (en) | 2001-02-12 |
CN1402847A (en) | 2003-03-12 |
CN100382047C (en) | 2008-04-16 |
CA2389168A1 (en) | 2001-05-03 |
AU768181B2 (en) | 2003-12-04 |
DE60039628D1 (en) | 2008-09-04 |
SE514318C2 (en) | 2001-02-12 |
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