{"title":"完美的页面放置","authors":"Thomas J. Murray, A. A. McRae, A. W. Madison","doi":"10.1145/2817460.2817472","DOIUrl":null,"url":null,"abstract":"Careful page placement policies are memory management heuristics that map virtual pages to physical memory in a manner that tends to reduce the average CPU cache conflict miss rate compared to random placement. Careful placement is particularly well-suited to large direct-mapped caches. Perfect page placement is the limiting case of careful placement and is achieved by a virtual page mapping that minimizes the conflict miss rate. Cache performance curves for perfect page placement are useful benchmarks for estimating the relative error of other careful placement policies. On-line perfect placement is not realizable because the computation requires future knowledge of the memory reference string. However, off-line perfect placement is a systems modeling tool analogous to the OPT page replacement policy for virtual memory systems; both policies are tools for computing upper bounds on memory system performance. In this paper, perfect page placement is presented and proved NP-hard for demand-paged virtual memory systems with direct-mapped caches and infinite physical memory capacity. A class of perfect placement approximation algorithms is also presented and proved NP-hard.","PeriodicalId":274966,"journal":{"name":"ACM-SE 35","volume":"63 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"1997-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":"{\"title\":\"Perfect page placement\",\"authors\":\"Thomas J. Murray, A. A. McRae, A. W. Madison\",\"doi\":\"10.1145/2817460.2817472\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Careful page placement policies are memory management heuristics that map virtual pages to physical memory in a manner that tends to reduce the average CPU cache conflict miss rate compared to random placement. Careful placement is particularly well-suited to large direct-mapped caches. Perfect page placement is the limiting case of careful placement and is achieved by a virtual page mapping that minimizes the conflict miss rate. Cache performance curves for perfect page placement are useful benchmarks for estimating the relative error of other careful placement policies. On-line perfect placement is not realizable because the computation requires future knowledge of the memory reference string. However, off-line perfect placement is a systems modeling tool analogous to the OPT page replacement policy for virtual memory systems; both policies are tools for computing upper bounds on memory system performance. In this paper, perfect page placement is presented and proved NP-hard for demand-paged virtual memory systems with direct-mapped caches and infinite physical memory capacity. A class of perfect placement approximation algorithms is also presented and proved NP-hard.\",\"PeriodicalId\":274966,\"journal\":{\"name\":\"ACM-SE 35\",\"volume\":\"63 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"1997-04-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"1\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"ACM-SE 35\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1145/2817460.2817472\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACM-SE 35","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1145/2817460.2817472","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Careful page placement policies are memory management heuristics that map virtual pages to physical memory in a manner that tends to reduce the average CPU cache conflict miss rate compared to random placement. Careful placement is particularly well-suited to large direct-mapped caches. Perfect page placement is the limiting case of careful placement and is achieved by a virtual page mapping that minimizes the conflict miss rate. Cache performance curves for perfect page placement are useful benchmarks for estimating the relative error of other careful placement policies. On-line perfect placement is not realizable because the computation requires future knowledge of the memory reference string. However, off-line perfect placement is a systems modeling tool analogous to the OPT page replacement policy for virtual memory systems; both policies are tools for computing upper bounds on memory system performance. In this paper, perfect page placement is presented and proved NP-hard for demand-paged virtual memory systems with direct-mapped caches and infinite physical memory capacity. A class of perfect placement approximation algorithms is also presented and proved NP-hard.