automatically exploiting cross-invocation parallelism using runtime ...

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Outer_Preheaderbr BB1ABB1A:ind1 = PHI [0, Outer_Preheader],[ind1.next, BB2]B:ind1.next = ind1 + 1c:p1 = ind1 >= ND:br p1, Sync_BlockBDCInner_PreheaderE:r1 = A[ind1]F:r2 = B[ind1]br BB2EFA B C DBB2G:ind2 = PHI [r1, Inner_Preheader],[ind2.next, BB3]H:ind2.next = ind2 + 1;I:p2 = ind2 > r2J:br p2, BB1HGIE FG H I JBB3K:r3 = getElementPtr(C[ind2])L:call update(r3)br BB2JKSync_Block(a) Pseudo IR codeKLLOuter_Preheaderbr BB1BB1(b) Dep. graph(c) DAGSCCA:ind1 = PHI [0, Outer_Preheader],[ind1.next, BB2]B:ind1.next = ind1 + 1c:p1 = ind1 >= ND:br p1, Sync_BlockInner_PreheaderE:r1 = A[ind1]F:r2 = B[ind1]br BB2BB2G:ind2 = PHI [r1, Inner_Preheader],[ind2.next, BB3]r4 = load TIME_STAMPPRODUCE(r4)r5 = r4 + 1store r5, TIMESTAMPPRODUCE (ind2)H:ind2.next = ind2 + 1I:p2 = ind2 > r2PRODUCE(p2)J:br p2, BB1BB3br BB2Sync_BlockPRODUCE_TO_ALL(END_TOKEN)(d) Scheduler partitionInner_Preheader'BB2't = CONSUME()p = t == END_TOKENbr p, Return_blockBB2''ind2 = CONSUME()p2 = CONSUME()br p2, Sync_BlockBB3'K:r3 = getElementPtr(C[ind2])L:call update(t3)br BB2'Sync_Block'br BB2'Return_Blockret(e) Worker partitionFigure 3.6: Running example for DOMORE code generation: (a) Pseudo IR for CG code;(b) PDG for example code. Dashed lines represent cross-iteration and cross-invocationdependences for inner loop. Solid lines represent other dependences between inner loopinstructions and outer loop instructions. (c) DAG SCC for example code. DAG SCC nodesare partitioned into scheduler and worker threads. (d) and (e) are code generated by DO-MORE MTCG algorithm (3.3.2).38
3.3.3 Scheduling IterationsDOMORE currently supports two scheduling strategies, round-robin and memory partitionbased scheduling. Round-robin is used by many parallelization techniques. Memorypartitioning (LOCALWRITE [26]) divides the memory space into disjoint chunks and assignseach chunk to a different worker thread, forming a one-to-one mapping. Iterationsare scheduled to threads that own the memory locations being touched by that iteration. Ifmultiple threads own the memory locations, that iteration is scheduled to all of them. LO-CALWRITE guarantees that each thread only updates its own memory space. DOMOREallows for the easy integration of other “smarter” scheduling techniques. Integration of awork stealing scheduler similar to Cilk [8] is planned as future work.39
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 24 and 25: 1.3 Dissertation OrganizationChapte
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
Page 34 and 35: These techniques are referred to as
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
Page 50 and 51: to T i . DOMORE’s MTCG follows th
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
Page 62 and 63: ations during the inspecting proces
Page 64 and 65: for (t = 0; t < STEP; t++) {L1: for
Page 66 and 67: sequential_func() {for (t = 0; t <
Page 68 and 69: Workerthread 1Workerthread 2Workert
Page 70 and 71: library provides efficient misspecu
Page 72 and 73: Workerthread 1TimeFigure 4.6: Timin
Page 74 and 75: 4.2 SPECCROSS Runtime System4.2.1 M
Page 76 and 77: takes up to 200MB memory space.To d
Page 78 and 79: checkpoint, the child spawns new wo
Page 80 and 81: Operation DescriptionFunctions for
Page 82 and 83: Main thread:main() {init();create_t
Page 84 and 85: implemented in the Liberty parallel
Page 86 and 87: Algorithm 5: Pseudo-code for SPECCR
Page 88 and 89: CROSS, since SPECCROSS can be appli
Page 90 and 91: techniques.Synchronization via sche
Page 92 and 93: Source Benchmark Function % of exec
Page 94 and 95: applied to the outermost loop, gene
Page 96 and 97: 5.2 SPECCROSS Performance Evaluatio
Page 98 and 99: and the number of checking requests
Page 100 and 101: 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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