XXXX年高性能计算国际会议论文(ICS XXXX)

PerformanceImpactandInterplayofSSDParallelismthroughAdvancedCommands,AllocationStrategyandDataGranularityYangHu,HongJiang,DanFeng,LeiTian,HaoLuo,ShupingZhangSchoolofComputer,HuazhongUniversityofScienceandTechnology,Wuhan,China,430074WuhanNationalLaboratoryforOptoelectronics,Wuhan,China,430074UniversityofNebraska-Lincoln,Lincoln,UnitedStates,68588BeijingInstituteofComputerTechnologyandApplication,Beijing,China,100039Correspondingauthor:[e-mail]{yanghu,hluo}@foxmail.com,[e-mail],[e-mail],[e-mail]pmentoftheNAND-Flashtechnology,NAND-FlashbasedSolid-StateDisk(SSD)hasbeenattractingagreatdealofattentionfrombothindustryandacademia.WhilearangeofSSDresearchtopics,frominterfacetechniquestobuffermanagementandFlashTranslationLayer(FTL),fromperfor-mancetoenduranceandenergyefficiency,havebeenextensivelystudiedintheliterature,theSSDbeingstudiedwasbyandlargetreatedasagreyorblackboxinthatmanyoftheinternalfeaturessuchasadvancedcommands,physical-pageallocationschemesanddatagranularityarehiddenorassumedaway.Wearguethat,basedonourexperimentalstudy,itistheseinternalfeaturesandtheirinterplaythatwillhelpprovidethemissingbutsignificantinsightstodesigninghigh-performanceandhigh-enduranceSSDs.Inthispaper,weuseourhighlyaccurateandmulti-tieredSSDsimulator,calledSSDsim,toanalyzeseveralkeyinternalSSDfactorstocharacterizetheirperformanceimpacts,interplayandparallelismsforthepurposeofperformanceandenduranceen-hancementofSSDs.Fromtheresultsofourexperiments,wefoundthat:(1)largerpagestendtohavesignificantlynegativeimpactonSSDperformanceundermanyworkloads;(2)differentphysical-pageallocationschemeshavedifferentdeploymenten-vironments,whereanoptimalallocationschemecanbefoundforeachworkload;(3)althoughadvancedcommandsprovidedbyflashmanufacturerscanimproveperformanceinsomecases,theymayjeopardizetheSSDperformanceandendurancewhenusedinappropriately;(4)sincetheparallelismsofSSDcanbeclassifiedintofourlevels,namely,channel-level,chip-level,die-levelandplane-level,thepriorityorderofSSDparallelism,resultingfromthestronginterplayamongphysical-pageallocationschemesandadvancedcommands,canhaveaverysignificantimpactonSSDperformanceandendurance.CategoriesandSubjectDescriptorsB.1.4[Hardware]:MicroprogramDesignAids–Firmwareengi-neering.B.3.3[MemoryStructure]:PerformanceAnalysisandDesignAids–Simulation.D.4.2[OperatingSystems]:StorageManagement–Secondarystorage.GeneralTermsMeasurementandPerformanceKeywordsNAND-Flash,SSD,simulator,advancedcommands,parallelism1.INTRODUCTIONNAND-FlashbasedSolidStateDrive(SSD)hasexperiencedtremendousdevelopmentandgrowthduringthelasttwodecades.Theenterprise-qualityFlashmemorystoragehasdroppedinprice,increasedinper-unitcapacity,improvedinreliability,andad-dressedtherandomwriteperformancepenalty,whichistradition-allyassociatedwiththetechnology,byvariousingeniousmethods[1-6].TheseadvantagesenableSSDstobewidelyusedinalmosteveryaspectofmoderncomputingsystems,fromlow-endPCstohigh-endserversinsupercomputing,thusmakingtheperformanceandenduranceissuesofsolid-statestoragesystemincreasinglyattractivetobothacademiaandindustry[7-11].SeveraltopicsrelatedtotheperformanceandenduranceofSSD,includingFTLdesigns[12-15]andbufferschemes[16-19],havebeenextensivelydiscussedintheliteratures.OtherstudiesintheliteraturededuceorinferthecharacteristicsofflashorSSDbyextendedmeasurement[20-23].However,someSSDinternalbehaviorswithpotentiallyimportantimpactsonthesystemper-formanceandendurancehavebeenlargelyignored.Whileverylittlehasbeenstudiedandreportedintheliteratureabouttheper-formanceandenduranceimpactsandinterplayofdatagranularityofSSD,allocationstrategyandadvancedcommands,ourexperi-enceswithSSDdesignandevaluationindicatethatjudicioususeofthesefeaturescanhavesignificantperformanceandenduranceimpacts.Forexample,wefoundthatdiverseallocationschemescanresultindifferentperformancelevelandthewayinwhichparallelisminSSDisexploitedcanbeakeyperformance-impactfactor.Moreover,whentheseinternalSSDbehaviorsdidgetdis-cussedintheliteraturetheywerestudiedinisolationwithoutcon-sideringtheirinterplayandinteraction[14][17][24-27].Infact,wefoundthatitisthisinterplayandinteractionamongthemthattendPermissiontomakedigitalorhardcopiesofallorpartofthisworkforpersonalorclassroomuseisgrantedwithoutfeeprovidedthatcopiesarenotmadeordistributedforprofitorcommercialadvantageandthatcopiesbearthisnoticeandthefullcitationonthefirstpage.Tocopyotherwise,orrepublish,topostonserversortoredistributetolists,requirespriorspecificpermissionand/orafee.ICS’11,May31–June4,2011,Tuscon,Arizona,USA.ACM978-1-4503-0102-2/11/05....$10.00.tohavethemostprofoundimpactonsystemperformanceandenduranceofSSD.Tothoroughlyinvestigatetheaforementionedperformanceim-pactandinterplayofSSDadvancedcommands,allocationstrategy,anddatagranularity,inthispaper,wecarefullyexamineseveralinternalbehaviorsrarelydiscussedintheliterature,whichmayhavepotentiallyimportantimpactontheperformanceandenduranceofSSD.Specifically,wecarryoutin-depthevaluationsofthesefea-turesandtheirinterplay,obt