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ID:33867539
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页数:46页
时间:2019-02-28
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1、UNIVERSITYofCALIFORNIASANTACRUZMANAGINGTHESOFTREAL-TIMEPROCESSESINRBEDAprojectreportsubmittedinpartialsatisfactionoftherequirementsforthedegreeofMASTEROFSCIENCEinCOMPUTERSCIENCEbyCaixueLinMarch2003TheprojectreportofCaixueLinisapproved:ProfessorScottA.BrandtProfessorEthan
2、L.MillerCopyright cbyCaixueLin2003AbstractManagingtheSoftReal-TimeProcessesinRBEDbyCaixueLinThispaperdescribestheimplementationofaResource-rateBasedEarliestDeadlineFirstscheduler(RBED).Theschedulerconsistsoftwoindependentcomponents:aresourceallocationpolicyandascheduling
3、algorithm.Itprovidesuniformschedulingforhardreal-time(HRT),softreal-time(SRT),andnon-real-timeprocesses.Weighted-proportionalResourceAllocationPolicy(WRAP)inRBEDensuresthetotalactualresourceusageofallprocessesisnomorethan1underallsituations.EachHRTprocessreservesafractio
4、noftheresources.SRTprocessesaremanagedtoreceivetheresourcewitharate(fraction)weightedproportionaltotheirtargetresourceusage.WRAPautomaticallyadjuststheresourceshareamongtheSRTprocesseswhentheloadchanges.Non-real-timeprocessesreceiveafairshareoftheleftoverresourcesbyHRTan
5、dSRTprocesses,buttheyneverstarveunderanysituationinRBED.Withresourceusagenomorethan1,theEDF-basedschedulingalgorithminRBEDal-waysfindsafeasiblescheduleforanysetofprocesses.Eachreal-timeprocess(includingHRTandSRT)isscheduledaccordingtoitsdeadline,whichmaybedynamicallyadjus
6、tedbecauseoftheloadchange.Non-real-timeprocessesarescheduledasSRTprocesseswiththeirpseudodeadlinesassignedbythescheduler.TheperformanceresultsdemonstrateRBED'sfeasibility(inunderloadedsituations)andflexibility(inoverloadedsituations)forfullyintegratedschedulingofHRT,SRT,a
7、ndnon-real-timeprocesses.ContentsAbstractiiiListofFiguresviiListofTablesixAcknowledgementsx1Introduction......................................11.1RBED.....................................22ResourceAllocationinRBED............................42.1ResourceDistributionandAdm
8、issionControlinRBED..........42.2ResourceAllocationforSRTprocesses...................63EDFSchedulinginR
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