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1.3 Dissertation OrganizationChapter 2 examines existing intra- and inter- invocation parallelization techniques, characterizingtheir applicability and scalability. This discussion motives DOMORE and SPEC-CROSS. Chapter 3 describes the design and implementation details of DOMORE, the firstnon-speculative runtime technique to exploit cross-invocation parallelism. DOMORE hasbeen published and presented in 2013 International Symposium on Code Generation andOptimization [28]. Chapter 4 introduces its speculative counterpart technique SPECCROSS.A quantitative evaluation of DOMORE and SPECCROSS is given in Chapter 5. Finally,Chapter 6 summarizes the conclusions of this dissertation and describes future avenues ofresearch.10
Chapter 2BackgroundImprecise and fragile static analyses limit the effectiveness of existing cross-invocationparallelization techniques. Addressing this vulnerability is the focus of this thesis. In thissection we explain the state of the art in automatic parallelization techniques. In Section2.1 we first identify the limitations of conventional analysis-based approaches to automaticparallelization. In Section 2.2 we provide a detailed discussion of current intra-invocationparallelization techniques, explaining how some of them compensate for the conservativenature of their analyses. Finally, in Section 2.3 we present existing cross-invocation parallelizationtechniques; in particular, how all of them rely on static analysis, which motivatesthe work of DOMORE and SPECCROSS.2.1 Limitations of Analysis-based Approaches in AutomaticParallelizationAutomatic parallelization is an ideal solution which frees programmers from the difficultiesof parallel programming and platform-specific performance tuning. Parallelizing compilerscan automatically parallelize affine loops [2, 7]. Loop A in Figure 2.1 shows an exampleloop. If a compiler proves that all memory variables in the body of the function foo do not11
Page 1 and 2: AUTOMATICALLY EXPLOITINGCROSS-INVOC
Page 4 and 5: techniques. Among twenty programs f
Page 6 and 7: in particular. Their professionalis
Page 8 and 9: ContentsAbstract . . . . . . . . .
Page 10 and 11: 4.5.4 Load Balancing Techniques . .
Page 12 and 13: 2.4 Sequential Loop Example for DOA
Page 14 and 15: 4.5 Overview of SPECCROSS: At compi
Page 16 and 17: 1.1 Limitations of Existing Approac
Page 18 and 19: advanced forms of parallelism (MPI,
Page 20 and 21: the graph stands for an iteration i
Page 22 and 23: 1.2 ContributionsFigure 1.5 demonst
Page 26 and 27: alias the array regular via inter-p
Page 28 and 29: 1 for (i = 0; i < M; i++){2 node =
Page 30 and 31: 1 cost = 0;2 node = list->head;3 Wh
Page 32 and 33: example which cannot benefit from e
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Page 36 and 37: unnecessary overhead at runtime.Tab
Page 38 and 39: Chapter 3Non-Speculatively Exploiti
Page 40 and 41: for a variety of reasons. For insta
Page 42 and 43: 12x11x10xDOMOREPthread Barrier9xLoo
Page 44 and 45: Algorithm 1: Pseudo-code for schedu
Page 46 and 47: Algorithm 2: Pseudo-code for worker
Page 48 and 49: 3.3 Compiler ImplementationThe DOMO
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Page 52 and 53: Outer_Preheaderbr BB1ABB1A:ind1 = P
Page 54 and 55: Algorithm 3: Pseudo-code for genera
Page 56 and 57: Scheduler Function SchedulerSync Fu
Page 58 and 59: SchedulerWorker1 Worker2Worker3Work
Page 60 and 61: 3.5 Related Work3.5.1 Cross-invocat
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Page 64 and 65: for (t = 0; t < STEP; t++) {L1: for
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4.2 SPECCROSS Runtime System4.2.1 M
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takes up to 200MB memory space.To d
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checkpoint, the child spawns new wo
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Operation DescriptionFunctions for
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Main thread:main() {init();create_t
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implemented in the Liberty parallel
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Algorithm 5: Pseudo-code for SPECCR
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CROSS, since SPECCROSS can be appli
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techniques.Synchronization via sche
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Source Benchmark Function % of exec
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applied to the outermost loop, gene
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5.2 SPECCROSS Performance Evaluatio
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and the number of checking requests
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8x7xno misspec.with misspec.Geomean
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This thesisPrevious workSpeedup (x)
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Program Speedup6x5x4x3x2xLOCALWRITE
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for DOMORE and SPECCROSS. Others (e
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programs and it achieves a geomean
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Bibliography[1] R. Allen and K. Ken
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[15] R. Cytron. DOACROSS: Beyond ve
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[31] T. B. Jablin, Y. Zhang, J. A.
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[47] A. Nicolau, G. Li, A. V. Veide
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[62] L. Rauchwerger and D. Padua. T
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national conference on Parallel Arc
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