Handling irregular ILP within conventional VLIW schedulers using artificial resource constraints

Rajagopalan, S.; Vachharajani, Manish; Malik, Sharad

doi:10.1145/354880.354902

Cited by 27 publications

(11 citation statements)

References 5 publications

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“…Therefore a covering of a complex real-world network by a small number of cliques may reveal its hidden structure [23]. Further applications of EDGE CLIQUE COVER can be found in such various areas as computational geometry [1], applied statistics [20,38], and compiler optimization [39]. Due to its importance, the EDGE CLIQUE COVER problem was studied from various perspectives, including approximation upper and lower bounds [2,32], heuristics [3,20,28,29,38,39] and polynomial-time algorithms for special graph classes [24,25,33,37].…”

Section: Edge Clique Covermentioning

confidence: 99%

Known Algorithms for Edge Clique Cover are Probably Optimal

Cygan¹,

Pilipczuk²,

Pilipczuk³

2016

SIAM J. Comput.

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In the EDGE CLIQUE COVER (ECC) problem, given a graph G and an integer k, we ask whether the edges of G can be covered with k complete subgraphs of G or, equivalently, whether G admits an intersection model on k-element universe. Gramm et al. [JEA 2008] have shown a set of simple rules that reduce the number of vertices of G to 2 k , and no algorithm is known with significantly better running time bound than a brute-force search on this reduced instance. In this paper we show that the approach of Gramm et al. is essentially optimal: we present a polynomial time algorithm that reduces an arbitrary 3-CNF-SAT formula with n variables and m clauses to an equivalent ECC instance (G, k) with k = O(log n) and |V (G)| = O(n + m). Consequently, there is no 2 2 o(k) poly(n) time algorithm for the ECC problem, unless the Exponential Time Hypothesis fails. To the best of our knowledge, these are the first results for a natural, fixed-parameter tractable problem, and proving that a doubly-exponential dependency on the parameter is essentially necessary.

show abstract

Section: Edge Clique Covermentioning

confidence: 99%

Known Algorithms for Edge Clique Cover are Probably Optimal

Cygan¹,

Pilipczuk²,

Pilipczuk³

2016

SIAM J. Comput.

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show abstract

“…Further applications of Edge Clique Cover can be found in such various areas as computational geometry [1], applied statistics [20,38], and compiler optimization [39]. Due to its importance, the Edge Clique Cover problem was studied from various perspectives, including approximation upper and lower bounds [2,32], heuristics [3,20,28,29,38,39] and polynomial-time algorithms for special graph classes [24,25,33,37].…”

Section: Edge Clique Covermentioning

confidence: 99%

Known algorithms for Edge Clique Cover are probably optimal

Cygan¹,

Pilipczuk²,

Pilipczuk³

2013

Proceedings of the Twenty-Fourth Annual ACM-SIAM Symposium on Discrete Algorithms

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In the Edge Clique Cover (ECC) problem, given a graph G and an integer k, we ask whether the edges of G can be covered with k complete subgraphs of G or, equivalently, whether G admits an intersection model on kelement universe. Gramm et al. [JEA 2008] have shown a set of simple rules that reduce the number of vertices of G to 2 k , and no algorithm is known with significantly better running time bound than a brute-force search on this reduced instance. In this paper we show that the approach of Gramm et al. is essentially optimal: we present a polynomial time algorithm that reduces an arbitrary 3-CNF-SAT formula with n variables and m clauses to an equivalent ECC instance (G, k) with k = O(log n) andpoly(n) time algorithm for the ECC problem, unless the Exponential Time Hypothesis fails. To the best of our knowledge, these are the first results for a natural, fixed-parameter tractable problem, and proving that a doubly-exponential dependency on the parameter is essentially necessary.

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“…We prove that this is impossible for machines that can be characterized by resource maps, which implies that it is impossible in the general case. Resource maps can be used to describe, among others, modern processors and machines with irregular constraints [31], as are often found in embedded processors. Theroem 1 proves that SHDP is not solvable for a general class of machines.…”

Section: Definitionmentioning

confidence: 99%

Automatic instruction scheduler retargeting by reverse-engineering

et al. 2006

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In order to generate high-quality code for modern processors, a compiler must aggressively schedule instructions, maximizing resource utilization for execution efficiency. For a compiler to produce such code, it must avoid structural hazards by being aware of the processor's available resources and of how these resources are utilized by each instruction. Unfortunately, the most prevalent approach to constructing such a scheduler, manually discovering and specifying this information, is both tedious and error-prone.This paper presents a new approach which, when given a processor or processor model, automatically determines this information. After establishing that the problem of perfectly determining a processor's structural hazards through probing is not solvable, this paper proposes a heuristic algorithm that discovers most of this information in practice. This can be used either to alleviate the problems associated with manual creation or to verify an existing specification. Scheduling with these automatically derived structural hazards yields almost all of the performance gain achieved using perfect hazard information.

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Handling irregular ILP within conventional VLIW schedulers using artificial resource constraints

Cited by 27 publications

References 5 publications

Known Algorithms for Edge Clique Cover are Probably Optimal

Known Algorithms for Edge Clique Cover are Probably Optimal

Known algorithms for Edge Clique Cover are probably optimal

Automatic instruction scheduler retargeting by reverse-engineering

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