CENG 3420 Computer Organization and Design. Lecture 07: Pipeline Review. Bei Yu

Transcription

1 CENG 3420 Compu gaizaio a Dig Lcu 07: Pipli Rviw Bi Yu CEG3420 L07.1 Spig 2016

2 Rviw: Sigl Cycl Diavaag & Avaag q U h clock cycl ifficily h clock cycl mu b im o accommoa h low i pcially poblmaic fo mo complx iucio lik floaig poi muliply Clk Cycl 1 Cycl 2 lw w Wa q May b waful of aa ic om fucioal ui (.g., a) mu b uplica ic hy ca o b ha uig a clock cycl bu q i impl a ay o ua CEG3420 L07.2 Spig 2016

3 Th Fiv Sag of Loa ucio Cycl 1 Cycl 2 Cycl 3 Cycl 4 Cycl 5 lw F D EX MEM WB q F: ucio Fch a Upa PC q D: Rgi Fch a ucio Dco q EX: Excu R-yp; calcula mmoy a q MEM: Ra/wi h aa fom/o h Daa Mmoy q WB: Wi h ul aa io h gi fil CEG3420 L07.3 Spig 2016

4 Sigl Cycl vu Pipli Sigl Cycl mplmaio (CC = 800 p): Cycl 1 Cycl 2 Clk lw w Wa Pipli mplmaio (CC = 200 p): 400 p lw F D EX MEM WB w F D EX MEM WB R-yp F D EX MEM WB q To compl a i iucio i h pipli ca ak 1000 p (a compa o 800 p fo h igl cycl ca). Why? q How log o ach ak o compl 1,000,000 a? CEG3420 L07.4 Spig 2016

5 MPS Pipli Daapah Aiio/Mo q Sa gi bw ach pipli ag o iola hm F:Fch D:Dc EX:Excu MEM: MmAcc WB: WiBack F/D D/EX EX/MEM A PC 4 ucio Mmoy Ra A Ra A 1 Rgi Ra Ra A 2Daa 1 Fil Wi A Ra Daa 2 Wi Daa Shif lf 2 A A Wi Daa Daa Mmoy Ra Daa MEM/WB Sig 16 Ex 32 Sym Clock CEG3420 L07.5 Spig 2016

6 Gaphically Rpig MPS Pipli q Ca hlp wih awig quio lik: How may cycl o i ak o xcu hi co? Wha i h oig uig cycl 4? h a haza, why o i occu, a how ca i b fix? CEG3420 L07.6 Spig 2016

7 h Pipli Sucu A Poibl q Wha abou h (low) muliply opaio? Mak h clock wic a low o l i ak wo cycl (ic i o u h DM ag) MUL q Wha if h aa mmoy acc i wic a low a h iucio mmoy? mak h clock wic a low o l aa mmoy acc ak wo cycl (a kp h am clock a) M Rg DM1 DM2 Rg CEG3420 L07.7 Spig 2016

8 Why Pipli? Fo Pfomac! Tim (clock cycl) c h pipli i full, o iucio i compl vy cycl, o CP = 1 4 Tim o fill h pipli CEG3420 L07.8 Spig 2016

9 Ca Pipliig G U o Toubl? q Y: Pipli Haza ucual haza: - a qui ouc i buy aa haza: - amp o u aa bfo i i ay cool haza: - ciig o cool acio p o pviou iucio q Ca uually olv haza by waiig pipli cool mu c h haza a ak acio o olv haza CEG3420 L07.9 Spig 2016

10 Rolv Sucual Haza 1 Tim (clock cycl). lw 1 Mm Rg Mm Rg Mm Rg Mm Rg Raig aa fom mmoy 2 3 Mm Rg Mm Rg Mm Rg Mm Rg 4 Raig iucio fom mmoy CEG3420 L07.10 Spig 2016 Mm Rg Mm Rg q Fix wih paa i a aa mmoi ($ a D$)

11 Rolv Sucual Haza 2 Tim (clock cycl). a $1, 1 2 a $2,$1, Fix gi fil acc haza by oig a i h co half of h cycl a wi i h fi half clock g ha cool gi wiig clock g ha cool loaig of pipli a gi CEG3420 L07.11 Spig 2016

12 Daa Haza q Dpci backwa i im cau haza. a $1, ub $4,$1,$5 a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 q Ra Af Wi (RAW) aa haza CEG3420 L07.12 Spig 2016

13 Daa Haza: Rgi Uag q Dpci backwa i im cau haza a $1, ub $4,$1,$5 a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 q Ra Af Wi (RAW) aa haza CEG3420 L07.13 Spig 2016

14 Daa Haza: Loa Mmoy q Dpci backwa i im cau haza. lw $1,4($2) ub $4,$1,$5 a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 q Loa-u aa haza CEG3420 L07.14 Spig 2016

15 Rolv Daa Haza 1: Sall. a $1, all Ca fix aa haza by waiig all bu impac CP all ub $4,$1,$5 a $6,$1,$7 CEG3420 L07.15 Spig 2016

16 Rolv Daa Haza 2: Fowaig. a $1, ub $4,$1,$5 Fix aa haza by fowaig ul a oo a hy a availabl o wh hy a a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 CEG3420 L07.16 Spig 2016

17 Rolv Daa Haza 2: Fowaig. a $1, ub $4,$1,$5 Fix aa haza by fowaig ul a oo a hy a availabl o wh hy a a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 CEG3420 L07.17 Spig 2016

18 Fowaig lluaio. a $1, ub $4,$1,$5 a $6,$7,$1 EX fowaig MEM fowaig G li: cocpual fowaig Blu li: al fowaig pah (fom gi o ipu) CEG3420 L07.18 Spig 2016

19 Y Aoh Complicaio! q Aoh poial aa haza ca occu wh h i a coflic bw h ul of h WB ag iucio a h MEM ag iucio which houl b fowa?. a $1,$1,$2 a $1,$1,$3 a $1,$1,$4 CEG3420 L07.19 Spig 2016

20 Y Aoh Complicaio! q Aoh poial aa haza ca occu wh h i a coflic bw h ul of h WB ag iucio a h MEM ag iucio which houl b fowa?. a $1,$1,$2 a $1,$1,$3 a $1,$1,$4 CEG3420 L07.20 Spig 2016

21 Mmoy-o-Mmoy Copi q Fo loa immialy follow by o (mmoy-ommoy copi) ca avoi a all by aig fowaig hawa fom h MEM/WB gi o h aa mmoy ipu. Woul o a a Fowa Ui a a mux o h MEM ag. lw $1,4($2) w $1,4($3) CEG3420 L07.21 Spig 2016

22 Fowaig wih Loa-u Daa Haza. lw $1,4($2) ub $4,$1,$5 a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 M Rg DM CEG3420 L07.22 Spig 2016

23 Fowaig wih Loa-u Daa Haza. lw $1,4($2) ub $4,$1,$5 a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 M Rg DM q Will ill o all cycl v wih fowaig CEG3420 L07.23 Spig 2016

24 Fowaig wih Loa-u Daa Haza. lw $1,4($2) all ub $4,$1,$5 a $6,$1,$7 o $8,$1,$9 xo $4,$1,$5 M Rg DM q Will ill o all cycl v wih fowaig CEG3420 L07.24 Spig 2016

25 Cool Haza q Wh h flow of iucio a i o quial (i.., PC = PC + 4); icu by chag of flow iucio Ucoiioal bach (j, jal, j) Coiioal bach (bq, b) Excpio q Poibl appoach Sall (impac CP) Mov ciio poi a aly i h pipli a poibl, hby ucig h umb of all cycl Dlay ciio (qui compil uppo) Pic a hop fo h b! q Cool haza occu l fquly ha aa haza, bu h i ohig a ffciv agai cool haza a fowaig i fo aa haza CEG3420 L07.25 Spig 2016

26 Cool Haza 1: Jump cu Sall q Jump o co uil D, o o fluh i To fluh, F.Fluh o zo h iucio fil of h F/D pipli gi (uig i io a op). j fluh Fix jump haza by waiig fluh j ag CEG3420 L07.26 Spig 2016 q Foualy, jump a vy ifqu oly 3% of h SPECi iucio mix

27 Cool Haza 2: Bach q Dpci backwa i im cau haza. bq lw 3 4 CEG3420 L07.27 Spig 2016

28 Way o Fix a Bach Cool Haza. bq fluh Fix bach haza by waiig fluh bu affc CP fluh fluh bq ag 3 M Rg DM CEG3420 L07.28 Spig 2016

29 Aoh Way o Fix a Bach Cool Haza q Mov bach ciio hawa back o a aly i h pipli a poibl i.., uig h co cycl. bq fluh Fix bach haza by waiig fluh bq ag 3 M Rg DM CEG3420 L07.29 Spig 2016

30 Schulig Bach Dlay Slo A. Fom bfo bach B. Fom bach ag C. Fom fall hough a $1,$2,$3 if $2=0 h lay lo ub $4,$5,$6 a $1,$2,$3 if $1=0 h lay lo q A i h b choic, fill lay lo a uc C a $1,$2,$3 if $1=0 h lay lo ub $4,$5,$6 bcom bcom bcom a $1,$2,$3 if $2=0 h if $1=0 h a $1,$2,$3 a $1,$2,$3 if $1=0 h ub $4,$5,$6 ub $4,$5,$6 q B a C, h ub iucio may o b copi, icaig C q B a C, mu b okay o xcu ub wh bach fail CEG3420 L07.30 Spig 2016

31 Fluhig wih Mipicio (No Tak). 4 bq $1,$2,2 8 ub $4,$1,$5 q To fluh h F ag iucio, a F.Fluh o zo h iucio fil of h F/D pipli gi (afomig i io a op) CEG3420 L07.31 Spig 2016

32 Fluhig wih Mipicio (No Tak). 4 bq $1,$2,2 8 fluh ub $4,$1,$5 16 a $6,$1,$7 20 o 8,$1,$9 q To fluh h F ag iucio, a F.Fluh o zo h iucio fil of h F/D pipli gi (afomig i io a op) CEG3420 L07.32 Spig 2016

33 Saic Bach Picio, co q Rolv bach haza by aumig a giv oucom a pocig 2. Pic ak pic bach will alway b ak Pic ak alway icu o all cycl (if bach iaio hawa ha b mov o h D ag) h a way o cach h a of h bach ag iucio?? q A h bach paly ica (fo p pipli), a impl aic picio chm will hu pfomac. Wih mo hawa, i i poibl o y o pic bach bhavio yamically uig pogam xcuio 3. Dyamic bach picio pic bach a uim uig u-im ifomaio CEG3420 L07.33 Spig 2016

34 Dyamic Bach Picio q A bach picio buff (aka bach hioy abl (BHT)) i h F ag a by h low bi of h PC, coai bi() pa o h D ag hough h F/D pipli gi ha ll whh h bach wa ak h la im i wa xcu Picio bi may pic icocly (may b a wog picio fo hi bach hi iaio o may b fom a iff bach wih h am low o PC bi) bu h o affc coc, ju pfomac - Bach ciio occu i h D ag af miig ha h fch iucio i a bach a chckig h picio bi() f h picio i wog, fluh h icoc iucio() i pipli, a h pipli wih h igh iucio, a iv h picio bi() - A 4096 bi BHT vai fom 1% mipicio (aa7, omcav) o 18% (qo) CEG3420 L07.34 Spig 2016

35 Bach Tag Buff q Th BHT pic wh a bach i ak, bu o o ll wh i ak o! A bach ag buff (BTB) i h F ag cach h bach ag a, bu w alo o fch h x quial iucio. Th picio bi i F/D lc which x iucio will b loa io F/D a h x clock g - Woul a wo a po iucio mmoy h BTB ca cach h bach ak iucio whil h iucio mmoy i fchig h x quial iucio PC BTB ucio Mmoy Ra 0 A q f h picio i coc, all ca b avoi o ma which icio hy go CEG3420 L07.35 Spig 2016

36 1-bi Picio Accuacy q q A 1-bi pico will b icoc wic wh o ak Aum pic_bi = 0 o a (iicaig bach o ak) a loop cool i a h boom of h loop co 1. Fi im hough h loop, h pico mipic h bach ic h bach i ak back o h op of h loop; iv picio bi (pic_bi = 1) 2. A log a bach i ak (loopig), picio i coc 3. Exiig h loop, h pico agai mipic h bach ic hi im h bach i o ak fallig ou of h loop; iv picio bi (pic_bi = 0) Loop: 1 loop i 2 loop i... la loop i b $1,$2,Loop fall ou i Fo 10 im hough h loop w hav a 80% picio accuacy fo a bach ha i ak 90% of h im CEG3420 L07.36 Spig 2016

37 2-bi Pico q A 2-bi chm ca giv 90% accuacy ic a picio mu b wog wic bfo h picio bi i chag Tak Tak Pic Tak Pic No Tak No ak Tak No ak Tak Pic Tak No ak Pic No Tak No ak Loop: 1 loop i 2 loop i... la loop i b $1,$2,Loop fall ou i CEG3420 L07.37 Spig 2016

38 2-bi Pico q A 2-bi chm ca giv 90% accuacy ic a picio mu b wog wic bfo h picio bi i chag igh 9 im 1 Tak 0 Tak Pic Tak 11 Pic 01 No Tak wog o loop fall ou No ak Tak igh o 1 iaio No ak Tak Pic 10 Tak 1 No ak 0 00Pic No Tak No ak Loop: 1 loop i 2 loop i... la loop i b $1,$2,Loop fall ou i q BHT alo o h iiial FSM a CEG3420 L07.38 Spig 2016