cache性能分析报告

1、计算机系统结构课内实验实验报告一、实验目的及要求1,加深对Cache的基本概念、基本组织结构以及基本工作原理的理解；2,了解Cache的容量、相联度、块大小对Cache性能的影响；3,掌握降低Cache失效率的各种方法，以及这些方法对Cache性能提高的好处；4,理解Cache失效的产生原因以及Cache的三种失效；5,理解LRU与随机法的基本思想，及它们对Cache性能的影响；二、实验环境Vmware虚拟机，redhat9,0linux操作系统，SimpleScalar模拟器三、实验内容1,运行SimpleScalar模拟器；2,在基本配置情况下运行程序（请指明所选的测试程序），统计Cach

2、e总失效次数、三种不同种类的失效次数；3,改变Cache容量（*2,*4,*8,*64）,运行程序（指明所选的测试程序），统计各种失效的次数，并分析Cache容量对Cache性能的影响；4,改变Cache的相联度（1路，2路，4路，8路，64路），运行程序（指明所选的测试程序），统计各种失效的次数，并分析相联度对Cache性能的影响；5,改变Cache块大小（*2,*4,*8,*64）,运行程序（指明所选的测试程序），统计各种失效的次数，并分析Cache块大小对Cache性能的影响；6.分别采用LRUW随机法，在不同的Cache容量、不同的相联度下，运行程序（指明所选的测试程序）统计Cache

3、总失效次数，计算失效率。分析不同的替换算法对Cache性能的影响。四、实验步骤1、关于simplescalar的简要说明SimpleScalar包括多个仿真器：sim-fast,simsafe,sim-cache,sim-cheetah,sim-pro和sim-outorder。本次实验使用的是sim-cache,下面说明一下sim-cache。sim-cache:在这个仿真中加入了cache,用户可以对cache及TLB进行设置，支持两级的cache和一级的TLB,第一级cache和TLB均分为数据和指令两部分。（摘自百度百科）下面简要说明一下有关cache的信息：一般来说，Cache勺结构

4、参数主要包括以下几个方面：容量、块大小、相联度、替换算法等。在SimpleScalar模拟器中，采用了两级Cache吉构，同时数据和指令Cach吩开。SimpleScalar的Cach卷数酉己置命令为：:Cached勺名称，其中:dl1:一级数据Cache;dl2:二级数据Cache;111 :一级指令Cache;112 :二级指令Cache;dtlb:数据TLBjitlb:指令TLB:组的数目；:块大小；:相联度；:替换策略。此时，Cache容量为：*。替换策略主要有以下几种：l:LRU最近最少使用；f:FIFO,先进先出；r:RANDOM随机策略。例如：-cache:dl1dl1:2048

5、:64:4:r,表示对一级数据cache进行配置，2048表示有2048组，64表示cache块大小为64byte,4表示相联度为4,r表示替换策略为RANDQ循此配置下，一级数据cache的容量为2048*64*4=512KB由于SimplescalarSpec2000测试程序在其官方网站不能下载，故使用simplescalar模拟器自带的测试程序以及自己设计的一个程序进行测试。我们所有的实验内容都是对一级数据cache来进行分析的。在simplescalar中，我们使用的模拟器是sim-cache。2、simplescalar模拟器基本配置情况下的运行模拟1 .用安装好的simplesca

6、lar中的编译器对test.c进行编译，编译后生成了能够在模拟器中可以运行的可执行文件。命令行运行界面如下图所示：2 .我们使用simplescalar中的模拟器sim-cache对a.out模拟执行，执行后的界面如下图所示：111,tebjjcksill.inva1ida1ions00#10la1munberli|janunberofwitebatksd1Jses4+20lu1nunberx?facccsssdll.hitiJfiS*id1iiuiibcr-ofhiLsd11l1tussfs+57IdLii1Ejnberofiiumd11即1口千瞧nt$2(n#ini1iiunherofre

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12、iunix?rofu】加modintjIilviTm1n)iypnsaluvaLrillolaI(irsiItveIphrftubIcmiisc5iclaIFglabIcjcctitfiitI集丫廿IpiL1libitiuu-3,对运行结果进行分析从上面的运行结果中我们提取出一级数据cache(dll)的信息进行分析：dll.accesses4420#totalnumberofaccesses一级数据cache上的总访问次数dll.hits3963#totalnumberofhits一级数据cache上的命中次数dll.misses457#totalnumberofmisses一级数据cach

13、e上的失效次数dll.replacements201#totalnumberofreplacements一级数据cache上发生替换的次数dll.writebacks190#totalnumberofwritebacks一级数据cache上发生写回的次数dll.invalidations0#totalnumberofinvalidations一级数据cache上无效访问的次数dl1.miss_rate0.1034#missrate(i.e.,misses/ref)一级数据cache上的失效率dl1.repl_rate0.0455#replacementrate(i.e.,repls/ref)一

14、级数据cache上发生替换的概率dl1.wb_rate0.0430#writebackrate(i.e.,wrbks/ref)一级数据cache上发生写回的概率dl1.inv_rate0.0000#invalidationrate(i.e.,invs/ref)一级数据cache上发生无效访问的概率从分析中，我们可以得出，一级数据cache总共的失效次数(dl1.misses)为457次，我们知道容量失效和冲突失效都发生了替换，所以它们的失效次数(dl1.replacements)总共为201次，强制性失效次数为457-201=256次。一级数据cache的总失效率为0.1034。3、Cache

15、容量对Cache性能的影响1 .操作说明：改变simplescalar模拟器中的一级数据cache(dl1)的容量配置，我们通过改变组数来改变它的容量。与此同时固定块大小为32byte、相联度为2以及替换策略为LRU?参数。2 .运行的界面(截取了部分所需的界面)如下图所示：d11.acceses57466Xdll.hi356071口dl,nissesIMSd11hreplanrnts1331Jdllkwrileb4icksS271dll.inva1idations0卡d11.miss_rjLe0.02434d1Krep1_rate0.0232#dll.wh.Tatc0.01443d11.in

16、v_rat000fl0也容&4KB(64*32*2*1)时，toljLnuiiberofaccetuLjLnunberothits,nlalnunberofmissesIaInunberofreplarenpntsIg1iIminbcrofwi-iteb.akstuLj1nuiiboiafinva1idulionsnumratemisse7re1)rep1afeiiEnlrate(iieL,rep1s/ref)urittbackratei.十Mibks/refiiivaIido1ionric(i.r.,inv/rrf)rocitfPOClIj!LOO暨(NCZChinJl111linplcii

17、m3incachecichcjd11dll132；322；Itcit曜Ih.L一。ID1C*W_I口A忆5。d11.3CCCSSC5574ftfitoL1nuiiiicrofacccsstsdll.hUi56626港ioLj1nunl止ro1hitsd1Jmi$e$S40fltuL2i1nniil)erImissesd11.rp1acrnpnts72totalnurrbero1TepBareiren1dllrutitehaksS4XflIminherofutilehacltndll.invalidationi;0fl1口”Iniivbcrofinva1idaiion?d11.iniM&_LO0

18、.014Gflmisirmt(Lt.imi容&8KB(128*32*2*1)时，2012100201bun.hnle/rMl/arrplrjflltr/sirtpkjim3.0tmil1Jilcbjcks359ifIgid1runberoI,vrilebacksd11,inva1idaticn0i口ia1nunberofinva1idaiinndl1.mifle0.0116misiirale(i.misses/ref)dll.repl_rjIO.OG72#ropIaccrrcntyate(i“也*,ropls/rofd11.vbraLe0.WG2fiuritcbsckrai.rMThkU史1)

19、dll.inv_rateLLDOUU#inva1id口tionr口te(i.rinvs/ref容量为64KB(1024*32*2*1)时,ill15再时NLcLi1nuiii)erOf学d1J.hits58924flLcla1nunte(athiimd11.mis542flIcsm1nunberofmissesdl1trepla(*enFnifl0RinialnunberofrpplnTwnrn1d11.ytitchuM$0Nl49tu1nunbcrofmtiiebackstill,inva1idiiions0lulunuiibcrofimj1idjiiuniJ11.ITU(-Eu山immis

20、srj(i-e*misscs/r-ef)dll.repl_ral-e0.0000#replacenrntrateRi上一rep1s/reT1dl1,iAt_ra1e.0000t（MTilebarkratetil-wrhk专/廿f)dll.invraten.ooooinva1idmionralefi.已一inv?/ref)frindtPf?fi121XiiSOfOTbituIiul-ldFiw】i八iirplmli八ii甲IfTrr：k。八iurtIim1lI11(11k1024;4221trath4、1.2.Cache相联度对Cache性能的影响操作说明改变simplescalar模拟器中的一

21、级数据cache的相联度大小。与此同时固定cache的容量16KB块大小32byte以及替换策略为LRU等参数。运行的界面（只截取了部分所需的界面）如下图所示：相联度为1路时，tqo1W(30131-OO62QIQdl1.vb_rateD.0044并itebsckrate(ie卜urbks/r*1f)JU.inv_rato0.(1000Ifin*1ida(ionriteCiinvs/ref相联度为2路时,dll.jccesse片dL.hits1H1E4Ad1.inises47tifldll.r*pJarcnnt!：2&ddll.wilebick22ttd11.invd1idak沁n*0ftdl

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23、i.c卜invsfrtfrdl1_raleU.MMlfiutiTebackise(i.e,.mtbk$/ref：1dlliinv_rite0.0000niiru1idution11ip(i.,invs/ref相联度为4路时，口miE何NT2nI2I11i|i1i|1Ir|/tiih|/-h.iit|i11-6-i-Iai/-.ih”Iti所,Ii&jirrl?ibtr.*“I11l|11iIJSt：2-Iif,11-fjs11Hh相联度为8路时,riM3*PC?ni?1!iri52OWrhiiulilllrll，fMH八iirplm八irriHr11rr.AiiitmiliriId11d11:

24、64HR:IInL“iithdll.accem0电与16639#luLu1minb电ofaeceiiedll.hits1617fllotaInumber0fhitsdllLITisses472inLaLnunberofnussedllijup1arcrrnts10#iotn1minberofreplaceurni$dllALTi1Cb4)?k7lotaInuiibcrofitchacksdll.inva1i_raic0.0004#xxriubackratei.EiWT4js/ref)dlltinv_ratrinraIidaiinnLe34jnvs/ref)相联度为64路时,too14PC2U1

25、21bin.Ii11le9Aroa1/e,irrplesealar/=.irrpksurn-inrcacbo-ciclhe：dJ1d11iki；Itesi-inulhJ11.3-cresses16SA9#LoLa1nuiiberofacceasdl1hits16169Niota1nunber5、Cache块大小对Cache性能的影响1 .操作说明改变simplescalar模拟器中的一级数据cache的块大小。与此同时固定Cache的容量为32KB相联度为2以及替换策略为LRU?参数。2 .运行的界面（只截取了部分所需的界面）如下图所示：块大小为8byte时，mttf-EijW1,2JIbin

26、.1i11Helf/rI/iirrpIraIjr/kirv|-1sim-Scini-rirh?-cacbridIdIh2U1X:K：2:1i电发Lprdll.hits529W4*Lola1nuiil)eifhi上dll.ITUEE13050kLQLHInuirbetofmii%esdll.rpUesdlJ.liH5303631loll1nunberofhitmd11Lmsses】Alota1iiuraberotmissesdW.rep52tota1nvntoerafreplacennisd11.witcback0#tota1miraberofitebacksd11.invd1hIjiiuiK0

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28、iche：d11dlhSII.42s2:1l-csmilldl1.accesses5314240lo1iiuiiberufacresdll.hits#lolaliiuiiberofhtlsd1.missee#Lnlalnuiiheit)fmissesd11.rapgcFn?nts3PtofaIiiunhernfreplacrrrmtsd11ilebacks廿Idla1iiLiirhernfwritbackftdll.ina1ida1ionsnftLal.a1nuirberofinva1idu(ionscl11.ini$s_rate0.U011ffrmsirdle(iLc.tin1?/rei)d

29、11Lrepl_rateU.000#repla-cenEntislerepLs/ef!d11,v.h,rate0、OOM#wiiirbackratr：i,1rbks/rtf)d11.inv_rale0.0000HinvaIidtionra(eiuvs/rtf当块大小为64byte时，打打加霜口。-h11lef/root/*irrpkf；calir/eirajileiinr3B0Rtureache-!1：dlJdl1：254?Hr2?11*s1-prhiliJ11.5S31424#loid1nuni）rot就配士电匕工史wtlI.h11sS31129用Lcla1nunberafhit工d11一而

30、雪we$#tnla1nuniierofrnisse?dll,rtpkepnriH：Io#ijla1oumterflfTeplacfiipni!；dll.witebacks#iola1nuinterofilehj-cksJ11.iliva1idatiohs0#loLalnunberofinud1iackraufi.E.DiTbks/rfdll.inv_T8i0.0000#inva1ida(ionrale(i.e.,invs/reD6、Cache的替换策略对Cache性能的影响1 .操作说明改变simplescalar模拟器中的一级数据cache的替换策略。与此同时固定Cache的块大小为32by

31、te、相联度为2。在Cache容量为2KB4KB8KB和64KB的情况下，分另进行测试。2 .运行的界面（只截取了部分所需的界面）如下图所示：容量为2KB时，使用了LRU?换策略（rod!中屿第bin.Iltlk#lit）：eint-eicl!dlldiLt3mJUL-Lh碑tl11Klch#-ed11dI：iJ：2：iHITJll.jcceses104T3#loinnuiibcrofaccc$学JIJ.hits”岫#Lcij1nunberothlKdII.nu54g4fltolainuiiberafmissesdlILreplaLenrnifl420atola1nunherofrephceu

32、rn1rJI.writebads$99ttLnluJnunberofiteback!idll.invB1idaiions0%LUin1nunberafinvj1idjilionsJ1J.iniS_fill-Eua?4(；2mi甘raLe(i、E-inissjcs/refdll.rep1_:al-eO.WIflrepUcenrnt二Le(iheTepIs/rtfdl1.曲居1efL03fiHmtitf*backratpi+e.ttThksfref)dll.invraten.flooo#inva1ida1ionrale(i.e*,invs/ref)容量为4KB时，使用了LRU?换策略CtuuhlC

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36、.031511ebacktei*七.wtbks/redll.inv_ratrk力。00#invalidatinrate卜in、*，f)容量为8KB时，使用了LRU策略(uocjLlFQO121JOSSOKZCbhi.1iltlr)1/ru-u1/sii/Ir5La.Idr/&iiipIcino5.0iin匚a小(ca4工：d】d.112肌3之一2二ILesL11疝邮11.acresse工IU473tutaLnuirbej,ofjccessesd11.h11s1HCUb#tuta1nurTbetofhiLMd1J.itiisses4!i5#tota1nunber(3fmis5esdll.rep1

37、acenrnisVWittota1nurrberofreplacerrpnind1Lwritebacks20()*tng1nurrbeiofitebacksdll.inv-a1idaliunsO*tutu1nurrbtrufinvaIidulioiihdll.mi5s_rateUJI444rrnarate(l.e.,rmsstsZref)d1J.rep1_raeOJI2UO#rrplcenenLrale(i.e,rep1fi/ref)d11.ub_rateOJH91TitebackraleCi.e.dxrbks/ref)d11hinv_rateO.ftOOOitinva1idaXinnra(i-invs/ref使用了RANDOM略1(LouLftSOlilOlu2ViCiLbJii.1iILIeJ/iuu1fiicrpDrscjIjgfiicrpIrsimJ.07sinicachecaclw;d11lIU.12占一52;31It占I1Id11.jcce&