Dynamic and Speculative Polyhedral Parallelization Using Compiler-Generated Skeletons

Jimborean, Alexandra; Clauss, Philippe; Dollinger, Jean-François; Loechner, Vincent; Caamaño, Juan Manuel Martinez

doi:10.1007/s10766-013-0259-4

Cited by 34 publications

(38 citation statements)

References 17 publications

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“…Different from others, the method evaluates speculative sections by quantitative values instead of qualitative value. Jimborean et al [76] proposed a framework based on algorithm skeletons for speculative parallelism. The skeleton is build at compiler time and is patched at runtime.…”

confidence: 99%

A Survey of Loop Parallelization: Models, Approaches, and Recent Developments

Ye¹,

Deng²,

Zou³

2016

IJGDC

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In cloud computing era, automatic parallelization is still significant for virtualization platform. However, after several decades of development, the overall effect is still to be improved. Summary of the mainstream technology developments will be beneficial to reveal the future direction and trend. This paper reviews the technology of loop parallelization, which is the key issue in automatic parallelization. After introducing the basic models and approaches, we focus on the recent developments, on which we obtain the trend of this field and the conclusions about future.

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confidence: 99%

A Survey of Loop Parallelization: Models, Approaches, and Recent Developments

Ye¹,

Deng²,

Zou³

2016

IJGDC

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“…Dynamic compilation is a well-studied area that has been shown to be useful in a number of problem domains [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”

Section: Dynamic Compilation For Optimizationmentioning

confidence: 99%

Protean Code: Achieving Near-Free Online Code Transformations for Warehouse Scale Computers

Laurenzano

Tang

Mars

2014

2014 47th Annual IEEE/ACM International Symposium on Microarchitecture

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Abstract-Rampant dynamism due to load fluctuations, corunner changes, and varying levels of interference poses a threat to application quality of service (QoS) and has limited our ability to allow co-locations in modern warehouse scale computers (WSCs). Instruction set features such as the non-temporal memory access hints found in modern ISAs (both ARM and x86) may be useful in mitigating these effects. However, despite the challenge of this dynamism and the availability of an instruction set mechanism that might help address the problem, a key capability missing in the system software stack in modern WSCs is the ability to dynamically transform (and re-transform) the executing application code to apply these instruction set features when necessary.In this work we introduce protean code, a novel approach for enacting arbitrary compiler transformations at runtime for native programs running on commodity hardware with negligible (<1%) overhead. The fundamental insight behind the underlying mechanism of protean code is that, instead of maintaining full control throughout the program's execution as with traditional dynamic optimizers, protean code allows the original binary to execute continuously and diverts control flow only at a set of virtualized points, allowing rapid and seamless rerouting to the new code variants. In addition, the protean code compiler embeds IR with high-level semantic information into the program, empowering the dynamic compiler to perform rich analysis and transformations online with little overhead. Using a fully functional protean code compiler and runtime built on LLVM, we design PC3D, Protean Code for Cache Contention in Datacenters. PC3D dynamically employs non-temporal access hints to achieve utilization improvements of up to 2.8x (1.5x on average) higher than state-of-the-art contention mitigation runtime techniques at a QoS target of 98%.

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“…The framework description focuses on the two main goals: building the polyhedral prediction model and applying speculative parallelization including runtime verification of the prediction. Further details regarding dynamic code generation and other important parts of Apollo can be found in [8], where a former prototype version called VMAD is presented. Apollo consists of two main parts: a static part implemented as passes of the LLVM compiler [9], and a dynamic part implemented as a runtime system written in C++.…”

Section: Dynamic and Speculative Polyhedral Parallelization With Apollomentioning

confidence: 99%

“…The instrumented version will run on a sample of the outermost loop iterations and the information acquired dynamically is used to build a prediction model of these statically non-analyzable memory accesses; (3) generates parallel code skeletons [8]. They are incomplete versions of the original loop nest and require runtime instantiation to generate the final code.…”

Section: Dynamic and Speculative Polyhedral Parallelization With Apollomentioning

confidence: 99%

“…Code skeletons: At compile-time, several variants of codes are generated from each loop nest that was marked in the source code by the user using the dedicated pragma: an instrumented version, as described in the previous subsection, but also a number of code skeletons, presented in detail in our previous work [8]. Skeletons can be seen as parametrized codes where the instantiation of their parameters results in the generation of a transformed optimized version of the target loop nest merging original computations and speculative parallelization management.…”

Section: Speculative Parallelization and Runtime Verificationmentioning

confidence: 99%

See 1 more Smart Citation

Speculative Program Parallelization with Scalable and Decentralized Runtime Verification

Sukumaran-Rajam

Caamaño

Wolff

et al. 2014

Runtime Verification

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Abstract. Thread Level Speculation (TLS) is a dynamic code parallelization technique proposed to keep the software in pace with the advances in hardware, in particular, to automatically parallelize programs to take advantage of the multicore processors. Being speculative, frameworks of this type unavoidably rely on verification systems that are similar to software transactional memory, and that require voluminous inter-thread communications or centralized registering of the performed memory accesses. The high degree of communication is against the basic principles of high performance parallel computing, does not scale with an increasing number of processor cores, and yields weak performance. Moreover, TLS systems often apply one unique parallelization strategy consisting in slicing a loop into several parallel speculative threads. Such a strategy is also against the basic principles since loops in the original serial code are not necessarily parallel and also, it is well-known that the parallel schedule must promote data locality which is crucial in obtaining good performance. This situation appeals to scalable and decentralized verification systems and new strategies to dynamically generate efficient parallel code resulting from advanced optimizing parallelizing transformations. Such transformations require a more complex verification system that allows intra-thread iterations to be reordered. In this paper, we propose a verification system of this kind, based on a model built at runtime and predicting a linear memory behavior. This strategy is part of the Apollo speculative code parallelizer which is based on an adaptation for dynamic usage of the polyhedral model.

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Dynamic and Speculative Polyhedral Parallelization Using Compiler-Generated Skeletons

Cited by 34 publications

References 17 publications

A Survey of Loop Parallelization: Models, Approaches, and Recent Developments

A Survey of Loop Parallelization: Models, Approaches, and Recent Developments

Protean Code: Achieving Near-Free Online Code Transformations for Warehouse Scale Computers

Speculative Program Parallelization with Scalable and Decentralized Runtime Verification

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