There have been several prefetching techniques to reduce penalties on consecutive cache misses of tight loadload dependences 19, 18, 22, 30, 28, 4, 9, 8, 31, 12. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. In other words, a recursive class would have selfreferential pointers and most likely corresponds to common recursive data structures like trees and linked lists. Taxonomy of data prefetching for multicore processors. Mowry, compilerbased prefetching for recursive data structures, in. Compiler and hardware support for effective instruction prefetching in modern processors. A cooperative hardwaresoftware approach zhenlin wang ydoug burger. Automatic compilerinserted prefetching for pointerbased. What kind of data structures are good for this type. Automatic compilerinserted prefetching for pointerbased applications. Oct 01, 2012 luk and mowry 1999 have demonstrated that compiler based prefetching can sometimes be extended to pointers as well.
Architectural support for programming languages and operating systems asplos 96, acm press, 1996, pp. Maintaining cache coherence through compilerdirected data prefetching. Watson research center current operating systems offer poor performance when a numeric applications working set does not fit in main memory. Correlation prefetching with a userlevel memory thread.
Of 10 programs with recursive data structures, prefetching all pointers when a node is visited improved performance by 4% to 31% in half of the programs. Supporting dynamic data structures on distributed memory machines. Compilerbased prefetching for recursive data structures, in. In proceedings of the seventh international conference on architectural support for programming languages and operating systems asplos vii, pages 222233, oct. In this paper, we expand the scope of automatic compilerinserted prefetching to also include the recursive data structures commonly found in pointerbased applications. Automatic compilerinserted io prefetching for outofcore applications. Data prefetching motivation l pointer chasing to prefetch d nodes ahead we have to dereference d pointers data prefetching state of the art l software and hardware techniques both hardware and software techniques are well studied software can make use compiler level program analysis of arrays, but. Our results show compilerinstrumented multichain prefetching improves. Most pointerbased data structures are allocated in heap memory. The decision of where to place prefetched data in the memory hierarchy is a fundamental design decision. Lectures 2627 compiler algorithms for prefetching data. A practical stride prefetching implementation in global. Compilerbased prefetching for recursive data structures chikeung luk and todd c.
Data prefetching using dual processors springerlink. Dependence based prefetching for linked data structures. While softwarecontrolled prefetching is an attractive technique for tolerating this latency, its success has been limited thus far to arraybased numeric codes. A prefetching technique for irregular accesses to linked data. Identifying and exploiting memory access characteristics. Mowry, compilerbased prefetching for recursive data structures, proc. Proceedings of the 7th annual conference on architectural support for programming languages and operating systems, october 1996, pp. An efficient compiler technique for code size reduction using reduced bitwidth isas. In this paper, a novel approach will be presented that enables transformations that were designed for regular loop structures to be applied to linked list data structures. Compilers typically implement software prefetching in the context of loop nest optimizer lno, which focuses on affine references in well.
Compiler based prefetching for recursive data structures chikeung luk and todd c. Mowrycompilerbased prefetching for recursive data structures. Mowry, compilerbased prefetching for recursive data structures, proceedings of the seventh international conference on architectural support for. Software prefetching issues fetches only for data that is likely to be used while hardware schemes tend data in a more speculative manner. When prefetching works, when it doesnt, and why jaekyu lee, hyesoon kim, and richard vuduc, georgia institute of technology in emerging and future highend processor systems, tolerating increasing cache miss latency and properly. The grp hardwaresoftware collaboration thus combines the accuracy of compilerbased program analysis with the performance potential of aggressive hardware prefetching, bringing the performance gap versus a perfect l2 cache under 20%. Compilerbased prefetching for recursive data structures.
This paper investigates compiler based prefetching for pointerbased applicationsin particular, those containing recursive data structures. Cache optimizations for data driven multithreading. Abstract compilerbased prefetching for recursive data. Tolerating latency through softwarecontrolled data prefetching. Keywords caches, prefetching, pointerbased applica tions, recursive data structures, compiler optimization, sharedmemory multiprocessors, performance.
Mowry, compilerbased prefetching for recursive data structures, in proceedings of the seventh international conference on architectural support for programming languages and operating systems, october 1996. We have found that the performance impact of compilerdirected prefetching on data mining applications is unpredictable. Maintaining cache coherence through compilerdirected data. Pdf compilerdirected contentaware prefetching for dynamic. Compilerdirected contentaware prefetching for dynamic data structures conference paper pdf available in parallel architectures and compilation techniques conference proceedings, pact. This talk will focus on software prefetching targeting recursive data structures rds l terminology. In multiprocessor systems of the smp sharedmemory multiprocessors or symmetric multiprocessors and the dsm. Exploiting dual datamemory banks in digital signal processors mazen a.
In proceedings of the 30th annual international symposium on microarchitecture micro, pages 314320, december 1997. This paper investigates compilerbased prefetching for pointerbased applicationsin particular, those containing recursive data structures. Luk and mowry, compiler based prefetching techniques for recursive data structures, asplos 96. C compiler based prefetching for recursive data structure. A practical stride prefetching implementation in global optimizer.
Recursively composed descriptors describe depthfirst tree traversals. Branchdirected and pointerbased data cache prefetching. Prefetching works well for data structures with regular memory access patterns, but less so for data structures such as trees, hash tables, and other structures in which the datum that will be used is not. Automatic compiler inserted prefetching for pointer based applications. Impact of compilerbased dataprefetching techniques on. Data structure recursion basics some computer programming languages allow a module or function to call itself. Mehrotra, data prefetch mechanisms for accelerating symbolic and numeric computation, phd thesis, dept.
Proceedings of the 7th international conference on architectural support for programming languages and operating systems, 1996, pp. Prefetching has been employed to overcome the latency of fetching data or instructions from or to memory. Architectural support for programming languages and operating systems, pp. Accelerating sequential programs on chip multiprocessors. Once the block comes back from memory, it is placed in a cache. Prefetching for a graphics shader microsoft technology. In proceedings of the 7 th international conference on architectural support for programming languages and operating systems, pages 222233. Adding a cache can provide faster access to needed instructions. Compilerbased prefetching for recursive data structures citeseerx. Compilerbased io prefetching for outofcore applications angela demke brown and todd c.
Compilerbased prefetching for recursive data structures ck luk, tc mowry proceedings of the seventh international conference on architectural support, 1996. Stride memory references are prime candidates for software prefetches on architectures with, and without, support for hardware prefetching. A practical stride prefetching implementation in global optimizer hucheng zhou. Luk and mowry, compilerbased prefetching techniques for recursive data structures, asplos 96. Similarly, indirect accesses to large array structures may face the same problem when both address and data accesses encounter cache misses. Predicting data cache misses in nonnumeric applications through correlation profiling. Machine learning techniques for improved data prefetching. Mowry, title compilerbased prefetching for recursive data structures, booktitle in proceedings of the seventh international conference on architectural support for programming languages and operating systems, year 1996, pages 222233. Data prefetching using offline learning request pdf. The problem here is simpler since prefetching is not necessary for correctness and only serves to improve performance. Design and evaluation of a compiler algorithm for prefetching. For todays increasingly powerconstrained multicore systems, integrating simpler and more energyefficient inorder cores becomes attractive.
However, since inorder processors lack complex hardwa. The contentdirected data prefetcher also takes advantage of the recursive construction of linked data structures. Ieee tc99 prefetch all the pointers children when a node is visited. Schedulerbased prefetching for multilevel memories. Our proposed techniques include three compilerbased. We introduce a dynamic scheme that captures the accesspatterns of linked data structures and can be used to predict future accesses with high accuracy. A programmable memory hierarchy for prefetching linked data. For size hints, the compiler can encode a variablesize regionthat speci. In proceedings of the seventh international conference on architectural support for programming languages and operating systems, pages 222233, october 1996. Clearly, data must be moved into a higher level of the memory hierarchy to provide a performance benefit.
Prefetching lecture cpu cache array data structure. Software data prefetching is a key technique for hiding memory latencies on modern high performance processors. Mowry, compiler based prefetching for recursive data structures, proc. Identifying and exploiting memory access characteristics for prefetching linked data structures by hassan fakhri alsukhni b. Compiler based prefetching for recursive data structures. This paper investigates compiler based prefetching for pointer based applicationsin particular, those containing recursive data structures. Computer systems are typically designed with multiple levels of memory hierarchy. Roth and sohi, effective jump pointer prefetching for linked data structures.
We identify the fundamental problem in prefetching pointerbased data structures and propose a guideline for devising successful prefetching schemes. A general framework for prefetch scheduling in linked data. While prefetching has enjoyed considerable success in arraybased numeric codes, its potential in pointerbased applications has remained largely unexplored. Usre45086e1 method and apparatus for prefetching recursive. While prefetching has enjoyed considerable success in array based numeric codes, its potential in pointer based applications has remained largely unexplored. A stateless, contentdirected data prefetching mechanism. Volume 53, issue 2, 15 september 1998, pages 144173. In computer architecture, instruction prefetch is a technique used in central processor units to speed up the execution of a program by reducing wait states prefetching occurs when a processor requests an instruction or data block from main memory before it is actually needed.
Lee, engin ipek, onur mutlu, and doug burger, architecting phase change memory as a scalable dram alternative. Compilerbased io prefetching for outofcore applications. In computer architecture, instruction prefetch is a technique used in microprocessors to speed up the execution of a program by reducing wait states modern microprocessors are much faster than the memory where the program is kept, meaning that the programs instructions cannot be read fast enough to keep the microprocessor busy. On the classification and evaluation of prefetching. Our technique exploits the dependence relationships that exist between loads that produce addresses and loads that consume these addresses. Irregular access patterns are a major problem for todays optimizing compilers. We identify the fundamental problem in prefetching pointer based data structures and propose a guideline for devising successful prefetching schemes. Impact of compilerbased dataprefetching techniques on spec omp application performance abstract. Mowry carnegie mellon university and orran krieger ibm t. In proceedings of the seventh international conference on architectural support for programming languages and operating systems, pages 222 233, 1996. A compilerdirected data prefetching scheme for chip.
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