Intermediate Language Design of High-level Language VMs: Towards Comprehensive Concurrency Support
- 1. Intermediate Language Designof High-level Language VMsTowards Comprehensive Concurrency SupportMichael HauptHassoPlattner InstituteUniversity of PotsdamTheo D’HondtSoftware Languages LabVrijeUniversiteitBrusselStefan MarrSoftware Languages LabVrijeUniversiteitBrusselVMIL Workshop, 25th October 2009, Orlando, Florida
- 2. AgendaMotivationSurvey DesignConcurrency SupportConclusionOutlook10/27/092IL Design For VMs, Stefan Marr, VMIL, Oct. 2009
- 3. MotivationVMs support concurrency insufficiently!Why? Because, we want multi-language VMsFast JITs, great GCsHow to design an intermediate language?To our knowledgeNo surveysNo overview of design space/tradeoffs10/27/093IL Design For VMs, Stefan Marr, VMIL, Oct. 2009
- 4. Survey DesignHow to design an intermediate language?10/27/09IL Design For VMs, Stefan Marr, VMIL, Oct. 20094
- 5. Survey Design10/27/095IL Design For VMs, Stefan Marr, VMIL, Oct. 2009Dis VM 4th ed.OTPR12Dalvik VM 1.05.1CLI/ECMA-3551.3JVM spec.1.46.0 svn2.6Ruby 1.8/1.9RubiniusV8 svn4.4Squeak 3.9TraceMonkeyAll trademarks and logos are the property of their respective owners.
- 6. Survey CriteriaSpecification vs. implementationAbstraction level of intermediate languageMachine modelRepresentation, instruction encodingInstruction categoriesArithmetic & logic, control flow, stack, …Optimizations10/27/096Survey Design
- 13. Concurrency supportHow to support concurrency in an intermediate language?10/27/09IL Design For VMs, Stefan Marr, VMIL, Oct. 200913
- 14. Reminder: MotivationVMs support concurrency insufficiently!Why? Because, we want multi-language VMsFast JITsGreat GCsAdd concurrency to intermediate language10/27/0914IL Design For VMs, Stefan Marr, VMIL, Oct. 2009
- 15. 10/27/0915IL Design For VMs, Stefan Marr, VMIL, Oct. 2009Why Concurrency in ILs?
- 16. Concurrency Support in the IL?10/27/0916IL Design For VMs, Stefan Marr, VMIL, Oct. 2009Dis VM 4th ed.OTPR12Dalvik VM 1.05.1CLI/ECMA-3551.3JVM spec.1.46.0 svn2.6Ruby 1.8/1.9RubiniusV8 svn4.4Squeak 3.9TraceMonkey
- 17. Concurrency Support in the IL?10/27/0917IL Design For VMs, Stefan Marr, VMIL, Oct. 2009Dis VM 4th ed.OTPR12Dalvik VM 1.05.1CLI/ECMA-3551.3JVM spec.1.46.0 svn2.6Ruby 1.8/1.9RubiniusV8 svn4.4Squeak 3.9TraceMonkeyonly 6 out of 17
- 18. Survey Criteria - ConcurrencyConcurrency supportConcurrency modelIncluded instructionsStandard library (stdlib)10/27/0918IL Design For VMs, Stefan Marr, VMIL, Oct. 2009
- 19. Common Language Infrastructurevolatile.(prefix instruction)marks a subsequent pointer referenceSynchronized methodsMemory modelAtomic read or write of certain aligned dataStandard libraryMemory barriers, atomic updatesParallel loops, futures,…10/27/0919Concurrency Support
- 20. Dis VM (spec. 4th ed.)Inspired by CommunicatingSequentialProcessesspawn – new threadnew* – new channelrecv, send – on given channelalt, nbalt – send or receive on ready channelMemory model unspecified10/27/0920Concurrency Support
- 21. ErlangActors modelsend, wait, wait_timeoutremove_messagetimeoutPure, functional languageNo memory model specifiedOnly high-level constructs in stdlib.10/27/0921Concurrency Support
- 22. Java Virtual Machinemonitorenter/-exitFor synchronized blocksSynchronized methodsMemory modelStandard libraryLow- and high-level constructsDalvikVM promises the same10/27/0922Concurrency Support
- 23. MozartLOCKTHREADNo unlockImplicit supportData-flow variables, distributionStandard libraryHigh-level constructsFutures, stream channels,…10/27/0923Concurrency Support
- 24. ConclusionWide range of supported modelsNo notion of multiple modelsOften limited to implicit semantics or guarantiesOften most functionality in standard library10/27/0924IL Design For VMs, Stefan Marr, VMIL, Oct. 2009
- 25. OutlookMulti-language VMs have toEnable language designer to invent new constructs/conceptsProvide low- and high-level constructsLow-level: Memory barriers, atomic updates, …High-level: Tuplespaces, STM, Actors, …Open question: tradeoffs IL vs. stdlib.10/27/0925IL Design For VMs, Stefan Marr, VMIL, Oct. 2009
- 26. Discussion10/27/0926IL Design For VMs, Stefan Marr, VMIL, Oct. 2009
Editor's Notes
- #3: The motivation for this survey is hopefully clear nowToday, I will present here only the survey designAnd the concurrency related features we found in the different VMs
- #4: Concurrency support for intermediate language
- #5: Let’s try to find an answer for this basic question
- #6: 17 VMscommon open source VMsResearch VMsand production VMsOut of the Box: directly usable by the application developer which uses the target language running on top of the VM
- #9: CLI and JVM are only VMs here which are used as multi-langueVMs
- #10: DisVMOnly SpecificationMem-mem model
- #11: Virtual Machine Showdown: Stack Versus Registersby: Yunhe Shi and Kevin Casey and M. Anton Ertl and David GreggIn: ACM Trans. Archit. Code Optim. , Vol. 4 , Nr. 4New York, NY, USA: ACM (2008) , p. 1--36.
- #12: Another interesting approach
- #13: How to approach VM design when you want a JIT
- #14: Lets now focus on the concurrency support
- #15: VM support for concurrency as it is today is insufficientOur basic idea: Add support to the IL
- #17: But lets come back to our survey.So what is the state of the art to concurrency support in Ils?
- #18: 17 VMscommon open source VMsResearch VMsand production VMsOut of the Box: directly usable by the application developer which uses the target language running on top of the VM
- #19: Basic Question for the Survey:How do VMs support concurrency models today?
- #20: Atomic: native word size 32/64bit, no update
- #25: Split up slide
- #27: I would like to discussion following thingsSuitability of chosen VMsValid reasons to chose JVM over something else? I.e. reasons to not use Lua?-Other platforms then TILE64 or CellBE, which might be interesting?Tradeoffs which should be investigatedThe final goal for my PhD is to cover the concurrency part of ISA/VM design as a cornerstone for multi-paradigm VMs