并行计算机体系结构.ppt

parallelcomputerarchitecture并行计算机体系结构lecture7theintroductionofmulticoreprocessor,april13,2009隋秀峰（sxf）,2019/12/19,theintroductionofmulticoreprocessor,2,主要内容,多核处理器发展的动力多核处理器需要解决的关键问题多核处理器的发展现状多核处理器中的新兴技术,2019/12/19,theintroductionofmulticoreprocessor,3,todaysprocessor,voltagelevelaflashlight(1volt)currentlevelanoven(250amps)powerlevelalightbulb(100watts)areaapostagestamp(1squareinch)performancegflops,2019/12/19,theintroductionofmulticoreprocessor,4,whatisthefutureneed?,performanceneedisneverendingcomplainsfromend-usersnowadaystomorrowskillerapplicationnextstep:howcanwegetto1tflops?,2019/12/19,theintroductionofmulticoreprocessor,5,tomorrowskillerapplication(rms),2019/12/19,theintroductionofmulticoreprocessor,6,多核发展的动力线延迟,considerthe1tflop/ssequentialmachine:datamusttravelsomedistance,r,togetfrommemorytocpu.toget1dataelementpercycle,thismeans1012timespersecondatthespeedoflight,c=3x108m/s.thusrexample:intelhyper-threadingchipmultiprocessing(cmp)-multi-coreprocessor,2019/12/19,theintroductionofmulticoreprocessor,18,micro-architecturetrends,2019/12/19,theintroductionofmulticoreprocessor,19,adaptedfromjohandegelas,questformoreprocessingpower,anandtech,feb.8,2005.,understandingsmtandcmp,2019/12/19,theintroductionofmulticoreprocessor,20,makeclearconcurrencyvs.parallelism,concurrency:twoormorethreadsareinprogressatthesametime:parallelism:twoormorethreadsareexecutingatthesametimemultiplecoresneeded,simultaneousmultithreading(smt),minimalresourcereplicationprovidesinstructionstooverlapmemorylatencyseparatethreadsexploitidleresources,2019/12/19,theintroductionofmulticoreprocessor,21,context1,context2,functionalunits,l1cache,l2cache,mainmemory,smt:simultaneousmultithreading,2019/12/19,theintroductionofmulticoreprocessor,22,superscalar,multithreaded,smt,issueslots,gototheeraofmulticore,concurrencyintheformofhardwaremultithreadinghasbeenaroundforawhile.usefulforhidingmemorylatencies.onlyabout30%performanceimprovementforspecialapplication.howcanwecontinuetoutilizetheever-highertransistordensitiespredictedbymooreslaw?currentview:cancontinueperformanceimprovementsbypackingmultipleprocessingcoresontoasinglechip,i.e.,multicore.multi-core=chipmultiprocessing=tera-scalecomputing,2019/12/19,theintroductionofmulticoreprocessor,23,chipmultiprocessing,muchlargerdegreeofresourcereplicationtwocompleteprocessingcoresoneachchipouterlevelsofcacheandexternalinterfacearesharedgreatlyreducedresourcecontentioncomparedtosmt,2019/12/19,theintroductionofmulticoreprocessor,24,l2cache,mainmemory,context1,context2,functionalunits,functionalunits,l1cache,l1cache,whatwebenefitfrommulti-core?,2019/12/19,theintroductionofmulticoreprocessor,25,newtargetformicro-architecturehighperformance/power,multi-coreprocessors,improvedcost/performanceratiominimalincreasesinarchitecturalcomplexityprovidesignificantincreasesinperformanceminimizesperformancestalls,withadramaticincreaseinoveralleffectivesystemperformancegreatereep(energyefficientperformance)andscalabilitycoresenablethread-levelparallelismmulti-corearchitectureenablesdivide-and-conquerstrategytoperformmoreworkinagivenclockcycle.,2019/12/19,theintroductionofmulticoreprocessor,26,multi-coreprocessors(cont.),whatsspecialformany-cores?explicitmulti-threadsrequiredtospeedupsingleapplicationperformancecoretocorecommunicationlatencyreducebandwidthincreasecachesizeper-corewillalsoreduce,2019/12/19,theintroductionofmulticoreprocessor,27,multi-coreprocessors(cont.),2019/12/19,theintroductionofmulticoreprocessor,28,intelclovertown上的延迟测试,2019/12/19,theintroductionofmulticoreprocessor,29,whatistheproblem?whereistheinnovation?,howaboutthecore?equaltotheoriginaloneornot?simplecoremaybeagoodchoosehowaboutthepowercontrolonchip?finegranularitypowercontrolhowabouttheinterconnectionbetweencoresandotherunits?xcoresmeansxtimesofmemoryreferencesrequireshigherthroughputsbetweencoresandcaches,withincachehierarchy,andbetweenlast-levelcacheandmemoryrequireslesslatenciesinthoseplacesfourbasickindsofinterconnectsbuses,crossbars,tiny-networks,andringseachhasitsowntradeoffsinthroughput,latency,resourceoccupation,andeaseofimplementationmaybesuitableatdifferentlevels,2019/12/19,theintroductionofmulticoreprocessor,30,whatistheproblem?whereistheinnovation?,howaboutthecache?(nuca:non-uniformcachearch.),2019/12/19,theintroductionofmulticoreprocessor,31,anucasubstrateforflexiblecmpcachesharing,proc.the19thannualinternationalconferenceonsupercomputing,june2005,pp.31-40,多核处理器的问题,多核处理器实际上是一个片上并行系统分层性分布性加速单个应用需要显式多线程多内核处理器系统对软件技术的核心问题是并行程序的开发问题，包括并行程序的编程与调试多核处理器的软件挑战,2019/12/19,theintroductionofmulticoreprocessor,32,whatistheproblem?whereistheinnovation?,wherearethethreads?maybethemostlargestchallengemakeprogrammerwritethreadingprogramstheworldmaybeconfused.automaticparallelismmissionimpossible,butcanimproveinsomesense.makemodulewiththreadingforusehowtocontrolhighlevelbehaviorofourprograms?trytoeasetheburdenofprogrammerlooksgood,buthowcan?,2019/12/19,theintroductionofmulticoreprocessor,33,如何应对多核上的软件挑战,让程序员进行并行编程继承和优化openmp和mpi等新的编程语言x10等事务内存(transactionalmemory)自动并行化难度大，经过20年的发展通用性仍不好推测多线程(speculativemulti-threading)实现并行库intelmkl、scalapack如何控制程序的高级行为?其他有价值的工作函数语言、数据流、领域语言,2019/12/19,theintroductionofmulticoreprocessor,34,allofabovearestillopenissues,2019/12/19,theintroductionofmulticoreprocessor,35,break！,2019/12/19,theintroductionofmulticoreprocessor,36,multicoreproductsnowadays,lotsofdual-coreproductsnow:intel:pentiumdandpentiumextremeedition,coreduo(2),woodcrest,montecitoibmpowerpcamdopteron/athlon64sunultrasparciv.systemswithmorethantwocoresareherewithmorecoming:ibmcell(asymmetric).dual-corepowerpcpluseight“synergisticprocessingelements”.sunniagaraeightcores,fourhyper-threadedthreadspercore.generalpurposecomputationongraphicsprocessors(gpgpu)intelexpectstoproduce16-oreven32-corechipswithinadecade.,2019/12/19,theintroductionofmulticoreprocessor,37,architectureofdual-corechips,2019/12/19,theintroductionofmulticoreprocessor,38,intelcoreduotwophysicalcoresinapackageeachwithitsownexecutionresourceseachwithitsownl1cache32kinstructionand32kdatabothcoressharethel2cache2mb8-waysetassociative;64-bytelinesize10clockcycleslatency;writebackupdatepolicy,amdopteronseparate1mbytel2cachesimprovementformemoryaffinityandthreadaffinity,intelmulti-coreplan,2019/12/19,theintroductionofmulticoreprocessor,39,cellfromibmandsony,2019/12/19,theintroductionofmulticoreprocessor,40,cellfromibmandsony,2019/12/19,theintroductionofmulticoreprocessor,41,niagarafromsun,2019/12/19,theintroductionofmulticoreprocessor,42,thetechnologiesunderway,rethinktheconcurrencyandparallelismformulti-corenewprogrammingmodelandprogramminglanguageshardwaresupport(andsoftware)formultithreadingcontrol-drivenspeculationspeculativemultithreadingdata-drivenspeculationprogramdemultiplexingarchitecturalthreadenhancementsupportforhardwarethreadslightweightsynchronization(monitor/mwait),2019/12/19,theintroductionofmulticoreprocessor,43,rethinkthecandpformulti-core,whatwehaveseenformulti-coremoreparallelismneedtobeexploitedscalingmaybemoreimportantmoreheterogeneityneedtobeexploitedtaskmappingmayberevisitedlowlatencyandhighbandwidthbetweencoresonchipfinegranularityparallelismmayberethinked,2019/12/19,theintroductionofmulticoreprocessor,44,rethinkthecandpformulti-core,makefulluseofmulti-coreresourcesmoreparallelismhidememoryaccessstallwell-knownmemorywall,2019/12/19,theintroductionofmulticoreprocessor,45,索引计算在clovertown上的测试,索引计算是计算密集与io密集并重的应用网页数据32gb，生成的索引大小为4.5gb,2019/12/19,theintroductionofmulticoreprocessor,46,索引计算在clovertown上的测试(续）,索引各个阶段，有的以计算为主，有的以io为主考虑将索引过程划分为多个流水段，实现流水索引算法，充分利用系统计算资源流水段的划分原则资源独立：各个流水段使用独立的资源时间接近：各个流水段的用时比较接近细粒度流水算法：利用流水段的重叠执行，实现并行化,2019/12/19,theintroductionofmulticoreprocessor,47,intelclovertown测试环境,2019/12/19,theintroductionofmulticoreprocessor,48,索引计算在clovertown上的测试(续）,单核上的性能提高流水线隐藏部分读文档i/o时间多核下的性能提高计算并行化,2019/12/19,theintroductionofmulticoreprocessor,49,性能提高8.2%,性能提高53.4%,测试时，使用1.5g内存，且待测数据和索引位于同一块磁盘,rethinkthecandpformulti-core,processoraffinitybenefitfortaskmappingparallelfftcomputationinnpbget14%performanceincreaseformpich,2019/12/19,theintroductionofmulticoreprocessor,50,rethinkthecandpformulti-core,exploitdynamicandadaptiveout-of-orderexecutionpatternsonmulti-coreandheterogeneoussystem,2019/12/19,theintroductionofmulticoreprocessor,51,thetechnologiesunderway,rethinktheconcurrencyandparallelismformulti-corenewprogrammingmodelandprogramminglanguageshardwaresupport(andsoftware)formultithreadingcontrol-drivenspeculationspeculativemultithreadingdata-drivenspeculationprogramdemultiplexingarchitecturalthreadenhancementsupportforhardwarethreadslightweightsynchronization(monitor/mwait),2019/12/19,theintroductionofmulticoreprocessor,52,programmingmodelandpls,bridgetheapplicationsoftwaretosystemsoftwareandhardwareforbetterexpressingtheparallelismforsuchheterogeneoussystemstransactionalmemoryibmx10sunfortress其它有意义的探索函数语言数据流领域语言,2019/12/19,theintroductionofmulticoreprocessor,53,transactionalmemoryawaytoeasethreadprogramming,threadprogrammingisaboringthing,2019/12/19,theintroductionofmulticoreprocessor,54,transactionalmemoryawaytoeasethreadprogramming,threadprogrammingisaboringthing,2019/12/19,theintroductionofmulticoreprocessor,55,transactionalmemoryawaytoeasethreadprogramming,atransactionisasequenceofmemoryloadsandstoresthateithercommitsorabortsifatransactioncommits,alltheloadsandstoresappeartohaveexecutedatomicallyifatransactionaborts,noneofitsstorestakeeffecttransactionoperationsarentvisibleuntiltheycommitorabortsimplifiedversionoftraditionalaciddatabasetransactions(nodurability,forexample),2019/12/19,theintroductionofmulticoreprocessor,56,transactionalmemoryexample,2019/12/19,theintroductionofmulticoreprocessor,57,problemsintransactionalmemory,2019/12/19,theintroductionofmulticoreprocessor,58,solutionsfortransactionalmemory,2019/12/19,theintroductionofmulticoreprocessor,59,x10,对多内核系统与集群系统提供统一的支持高生产率语言设计注重可移植性和安全性性能扩展了java虚拟机提供手工性能调整的手段在java语言基础上开发继承了java语言的核心价值-高生产率，可移植性，成熟、安全面向主流java/c/c+程序员,2019/12/19,theintroductionofmulticoreprocessor,60,x10vision:portableproductiveparallelprogramming,2019/12/19,theintroductionofmulticoreprocessor,61,x10places,physicalpes,x10languagedefinesmappingfromx10objectsasynca1;asynca2;tryfinishactivitya0(part2);asynca3;asynca4;catch()activitya0(part3);,activitya3,thetechnologiesunderway,rethinktheconcurrencyandparallelismformulti-corenewprogrammingmodelandprogramminglanguageshardwaresupport(andsoftware)formultithreadingcontrol-drivenspeculationspeculativemultithreadingdata-drivenspeculationprogramdemultiplexingarchitecturalthreadenhancementsupportforhardwarethreadslightweightsynchronization(monitor/mwait),2019/12/19,theintroductionofmulticoreprocessor,64,speculativemultithreading,2019/12/19,theintroductionofmulticoreprocessor,65,problemsinspeculativemultithreading,locatethesectionoftheprogramthatcanefficientlybeexecutedinparallelpre-computationslicehaslowcomputationaloverheadworkloadbalancelowoverheadforpre-computationslicebufferingandmulti-versioninginthememoryhierarchybufferingwillkeepthespeculativestatusuntilthethreadisverifiedandcanbecommittedmulti-versioningalloweachvariabletohaveadifferentvalueforeachofthethreadsrunninginparallelcheckdatadependencemis-speculationsquickly,2019/12/19,theintroductionofmulticoreprocessor,66,summaryforcurrenttrends,tomanycorehardwaresupportformultithreadingtransactionmemoryhardtowritefastthreadedprogramslockscreatefundamentalproblemstransactionalmemoryshieldsprogrammershardwarespeedsuptransactionalmemoryenergy-efficientdesign,2019/12/19,theintroductionofmulticoreprocessor,67,addmoreaxestothemicro-archit