Efficient Memory Management for Message-Passing Concurrency

114 Pages·2012·0.98 MB·English

IT Licentiate theses
2005-001
Efficient Memory Management
for Message-Passing Concurrency
Part I: Single-threaded execution
JESPER WILHELMSSON
UPPSALA UNIVERSITY
Department of Information Technology

Efficient Memory Management
for Message-Passing Concurrency
Part I: Single-threaded execution
BY
JESPER WILHELMSSON
May 2005
COMPUTING SCIENCE DIVISION
DEPARTMENT OF INFORMATION TECHNOLOGY
UPPSALA UNIVERSITY
UPPSALA
SWEDEN
DissertationforthedegreeofLicentiateofPhilosophyin ComputerScience
atUppsalaUniversity2005
Efficient Memory Management
for Message-Passing Concurrency
Part I: Single-threaded execution
JesperWilhelmsson
[email protected]
ComputingScienceDivision
DepartmentofInformationTechnology
UppsalaUniversity
Box337
SE-75105 Uppsala
Sweden
http://www.it.uu.se/
(cid:13)c JesperWilhelmsson2005
ISSN1404-5117
Printedby theDepartmentofInformationTechnology,Uppsala University,Sweden
Abstract
Manualmemory managementis errorprone. Some of the errorsit causes, in par-
ticular memory leaks and dangling pointers, are hard to find. Manual memory
management becomes even harder when concurrency enters the picture. It there-
fore gets more and more important to overcome the problems of manual memory
management in concurrent software as the interest in these applications increases
withthedevelopmentofnew,multi-threaded,hardware.
To ease the implementation of concurrent software many programming lan-
guagesthesedayscomewithautomaticmemorymanagementandsupportforcon-
currency. This support, called the concurrency model of the language, comes in
manyflavors(shareddatastructures,messagepassing,etc.). Theperformanceand
scalability of applications implemented using such programming languages de-
pendsonthe concurrency model, thememoryarchitecture,andthe memoryman-
ager used by the language. It is therefore important to investigate how different
memory architectures and memory management schemes affect the implementa-
tionofconcurrentsoftwareandwhatperformancetradeoffs areinvolved.
This thesis investigates ways of efficiently implementing the memory archi-
tecture and memory manager in a concurrent programming language. The con-
currency model which we explore is based on message passing with copying se-
mantics. We start by presenting the implementation of three different memory
architectures for concurrent software and give a detailed characterization of their
prosandconsregardingmessagepassingandefficiencyintermsofmemoryman-
agement. The issue examined is whether to use private memory for all processes
in a program or if there may be benefits in sharing all or parts of the memory. In
one of the architectures looked at, called hybrid, a static analysis called message
analysisisusedtoguidetheallocationofmessagedata.
Becausethehybridarchitectureistheenablingtechnologyforascalablemulti-
threadedimplementation,wethenfocusonthehybridarchitectureandinvestigate
how to manage the memory using different garbage collection techniques. We
presentprosandconsofthesetechniquesanddiscusstheircharacteristicsandtheir
performance in concurrent applications. Finally our experiences from turning the
garbagecollector incrementalare presented. The effectiveness of the incremental
collector is compared to the non-incrementalversion. On a wide range of bench-
marks,theincrementalcollectorwepresentisabletosustainhighmutatorutiliza-
tion(about80%duringcollectioncycles)atalowcost.
Thisworkisimplementedinanindustrial-strengthimplementationofthecon-
current functional programming language ERLANG. Our eventual goal is to use
the hybrid architecture and the incremental garbage collector as the basis for an
efficient multi-threaded implementation of ERLANG. The work described in this
thesisisabigstepinthatdirection.

Acknowledgments
FirstofallIwouldliketothankmysupervisor, KonstantinosSagonas,foroffering
me a PhD position, showing genuine interest in and providing constructive feed-
backonmy work. Hehasmany timespointedmein therightdirectionandgiven
mepapersfromwhichIhavegottenseveralgoodideas. Iamalsoindebtedforall
theefforthespendsinshowingmewhatscienceisaboutandhowtopursueit.
Erik ’Happi’ Stenman and Mikael Pettersson deserve my gratitude for their
effort and time helping me sort out the bugs in the implementation of the shared
and hybrid memory architectures which underlie this thesis. Many thanks go to
myfellowPhDstudentsintheHiPEteamaswell,RichardCarlsson,authorofthe
message analysisused in this work, Per Gustafsson, and TobiasLindahl, for their
helpinbouncingideasandveryenjoyableon-andoff-topicdiscussions.
Iwouldlike tothankBjo¨rnGustavsson oftheEricsson/OTP teamforthehelp
testingtheimplementationofthisworkandforfixingbugsinErlang/OTPtriggered
by this work. I would also like to thank the NETSim team and David Wallin for
providingmewithreal-worldbenchmarksandhelpingmeusetheirtools.
This research has been supported in part by grant #621-2003-3442 from
the Swedish Research Council (Vetenskapsra˚det) and by the ASTEC (Advanced
Software Technology) competence center with matching funds by Ericsson and
T-Mobile.
Finally I want to thank Camilla for all her love, patience and time. Camilla,
thisworkwouldnothavebeenpossiblewithoutyoursacrifices.
ThisthesisisdedicatedtoOliver.

List of Appended Papers
Themainpartofthisthesisconsistsofthefollowingthreepapers. Werefertothese
papersasPaperA,PaperB,andPaperC.
PaperA ErikJohansson,KonstantinosSagonas,andJesperWilhelmsson. Heap
architectures for concurrent languages using message passing. In Proceed-
ings of ISMM’2002: ACM SIGPLAN International Symposium on Memory
Management, pages88-99,NewYork,N.Y.,USA,June2002. ACMPress.
PaperB Richard Carlsson, Konstantinos Sagonas, and Jesper Wilhelmsson.
Messageanalysisforconcurrentlanguages. InStaticAnalysis: Proceedings
of the 10th International Symposium, number 2694 in LNCS, pages 73-90,
Berlin,Germany,June2003. Springer.
PaperC Konstantinos Sagonas and Jesper Wilhelmsson. Message analysis-
guided allocation and low-pause incremental garbage collection in a con-
current language. In Proceedings of ISMM’2004: ACM SIGPLAN Interna-
tional Symposium on Memory Management, pages 1-12, New York, N.Y.,
USA,October2004. ACMPress.