ECE 361 Computer Architecture Lecture 13: Designing a Pipeline Processor

Transcription

1 ECE 361 Compu Achicu Lcu 13: Digig a Pipli Poco 361 haza.1 Rviw: A Pipli Daapah Clk fch Rg/Dc Exc Mm W RgW Exp p Bach PC 1 0 PC+4 A Ui F/D Rgi PC+4 mm16 R Ra Rb R RFil R Rw Di R D/Ex Rgi 0 1 PC+4 mm16 bua bub Exc Ui Ex/Mm Rgi Zo Daa Mm RA Do WA Di Mm/W Rgi 1 Mux 0 RgD Sc MmW MmoRg 361 haza.2 1

2 Rviw: Pipli Cool Daa Saioay Cool Th Mai Cool ga h cool igal uig Rg/Dc Cool igal fo Exc (Exp, Sc,...) a u 1 cycl la Cool igal fo Mm (MmW Bach) a u 2 cycl la Cool igal fo W (MmoRg MmW) a u 3 cycl la Rg/Dc Exc Mm W Exp Exp Sc Sc F/D Rgi Mai Cool p RgD MmW Bach MmoRg D/Ex Rgi p RgD MmW Bach MmoRg Ex/Mm Rgi MmW Bach MmoRg Mm/W Rgi MmoRg RgW RgW RgW RgW 361 haza.3 Rviw: Pipli Summay Pipli Poco: Naual hacm of h mulipl clock cycl poco Each fucioal ui ca oly b u oc p iucio f a iucio i goig o u a fucioal ui: - i mu u i a h am ag a all oh iucio Pipli Cool: - Each ag cool igal p NLY o h iucio ha i culy i ha ag 361 haza.4 2

3 uli of Toay Lcu Rcap a oucio oucio o Haza Fowaig 1 cycl Loa Dlay 1 cycl Bach Dlay Wha mak pipliig ha Summay 361 haza.5 o ha ay fo compu Limi o pipliig: Haza pv x iucio fom xcuig uig i iga clock cycl ucual haza: HW cao uppo hi combiaio of iucio aa haza: iucio p o ul of pio iucio ill i h pipli cool haza: pipliig of bach & oh iucio ha chag h PC Commo oluio i o all h pipli uil h haza i olv, iig o o mo bubbl i h pipli 361 haza.6 3

4 Sigl Mmoy i a Sucual Haza. Loa Mm Rg Mm Rg Mm Rg Mm Rg Mm Mm Rg Mm Rg Rg Mm Rg Mm Rg Mm Rg 361 haza.7 pio 1: Sall o olv Mmoy Sucual Haza. Loa 1 2 3(all) 4 Mm Rg Mm Rg Mm Rg Mm Rg Mm Rg Mm Rg bubbl Mm Rg Mm Rg Mm Rg Mm Rg 361 haza.8 4

5 pio 2: Duplica o Rolv Sucual Haza Spaa ucio Cach (m) & Daa Cach (Dm). Loa m Rg Dm Rg 361 haza.9 Daa Haza o 1 a 1,2,3 ub 4, 1,3 a 6, 1,7 o 8, 1,9 xo 10, 1, haza.10 5

6 Daa Haza o 1: (Figu 6.30, pag 397, P&H) Dpci backwa i im a haza. F D/RF EX MEM WB a 1,2,3 ub 4,1,3 a 6,1,7 o 8,1,9 xo 10,1,11 m Rg Dm Rg 361 haza.11 pio1: HW Sall o Rolv Daa Haza Dpci backwa i im a haza. F D/RF EX MEM WB a 1,2,3 ub 4, 1,3 a 6,1,7 o 8,1,9 xo 10,1,11 m bubbl bubbl bubbl Rg Dm Rg m Rg Dm m Rg m Rg 361 haza.12 6

7 Bu call u of Daa Saioay Cool Th Mai Cool ga h cool igal uig Rg/Dc Cool igal fo Exc (Exp, Sc,...) a u 1 cycl la Cool igal fo Mm (MmW Bach) a u 2 cycl la Cool igal fo W (MmoRg MmW) a u 3 cycl la Rg/Dc Exc Mm W F/D Rgi Mai Cool Exp Sc p RgD MmW Bach MmoRg RgW D/Ex Rgi Exp Sc p RgD MmW Bach MmoRg RgW Ex/Mm Rgi MmW Bach MmoRg RgW Mm/W Rgi MmoRg RgW 361 haza.13 pio 1: How HW ally all pipli. HW o chag PC => kp fchig am iucio & cool igal o big valu (0) F D/RF EX MEM WB a 1,2,3 all all all ub 4,1,3 m bubbl bubbl bubbl bubbl m bubbl bubbl bubbl bubbl m bubbl bubbl bubbl bubbl a 6,1,7 m Rg Dm 361 haza.14 7

8 pio 2: SW i ip iucio Wo ca i NP iucio. F D/RF E MEM WB m Rg X Dm Rg a 1,2,3 op op op ub 4,1,3 m Rg Dm Rg a 6,1,7 m Rg Dm 361 haza.15 Quio a Amiiaiv Ma 361 haza.16 8

9 pio 3 igh: Daa i availabl! ) Pipli gi alay coai aa. F D/RF E MEM WB m Rg X Dm Rg a 1,2,3 ub 4,1,3 a 6,1,7 o 8,1,9 xo 10,1,11 m Rg Dm Rg 361 haza.17 HW Chag fo Fowaig (Bypaig):) ca muliplxo o a pah fom pipli gi Aum gi a uig wi g w valu (ohwi mo ul o b fowa) 361 haza.18 9

10 Clock Fom La Lcu: Th Dlay Loa Phomo Cycl 1 Cycl 2 Cycl 3 Cycl 4 Cycl 5 Cycl 6 Cycl 7 Cycl 8 0: Loa fch Rg/Dc Exc Mm W Plu 1 fch Rg/Dc Exc Mm W Plu 2 fch Rg/Dc Exc Mm W Plu 3 fch Rg/Dc Exc Mm W Plu 4 fch Rg/Dc Exc Mm W Alhough Loa i fch uig Cycl 1: Th aa i NT wi io h Rg Fil uil h of Cycl 5 W cao a hi valu fom h Rg Fil uil Cycl 6 3-iucio lay bfo h loa ak ffc 361 haza.19 Fowaig uc Daa Haza o 1 cycl:. F D/RF EX MEM WB lw 1, 0(2) ub 4,1,6 a 6,1,7 o 8,1,9 m Rg Dm Rg 361 haza.20 10

11 pio1: HW Sall o Rolv Daa Haza lock : chck fo haza & all. F D/RF EX MEM WB lw 1, 0(2) all ub 4,1,3 a 6,1,7 o 8,1,9 m bubbl bubbl bubbl bubbl m Rg Dm Rg 361 haza.21 pio 2: SW i ip iucio. Wo ca i NP iucio MPS oluio: No HW chckig F D/RF EX MEM WB lw 1, 0(2) op ub 4,1,3 a 6,1,7 o 8,1,9 m Rg Dm Rg 361 haza.22 11

12 Sofwa Schulig o Avoi Loa Haza Ty poucig fa co fo a = b + c; = f; aumig a, b, c,,, a f i mmoy. Slow co: ADD SW SUB SW Rb,b Rc,c Ra,Rb,Rc a,ra R, Rf,f R,R,Rf,R 361 haza.23 Sofwa Schulig o Avoi Loa Haza Ty poucig fa co fo a = b + c; = f; aumig a, b, c,,, a f i mmoy. Slow co: ADD SW SUB SW Rb,b Rc,c Ra,Rb,Rc a,ra R, Rf,f R,R,Rf,R Fa co: ADD SW SUB SW Rb,b Rc,c R, Ra,Rb,Rc Rf,f a,ra R,R,Rf,R 361 haza.24 12

13 Compil Avoiig Loa Sall: chul uchul gcc pic x 14% 25% 31% 42% 54% 65% 0% 20% 40% 60% 80% % loa allig pipli 361 haza.25 Fom La Lcu: Th Dlay Bach Phomo Cycl 4 Cycl 5 Cycl 6 Cycl 7 Cycl 8 Cycl 9 Cycl 10 Cycl 11 Clk 12: Bq fch Rg/Dc Exc Mm W (ag i 1000) 16: R-yp fch Rg/Dc Exc Mm W 20: R-yp fch Rg/Dc Exc Mm W 24: R-yp fch Rg/Dc Exc Mm W 1000: Tag of B fch Rg/Dc Exc Mm W Alhough Bq i fch uig Cycl 4: Tag a i NT wi io h PC uil h of Cycl 7 Bach ag i NT fch uil Cycl 8 3-iucio lay bfo h bach ak ffc 361 haza.26 13

14 Cool Haza o Bach: 3 ag all 361 haza.27 Bach Sall mpac f CP = 1, 30% bach, Sall 3 cycl => w CP = 1.9! 2 pa oluio: Dmi bach ak o o oo, AND Compu ak bach a ali MPS bach = 0 o 0 Soluio pio 1: Mov Zo o D/RF ag A o calcula w PC i D/RF ag 1 clock cycl paly fo bach v haza.28 14

15 pio 1: mov HW fowa o uc bach lay ucio Fch. Dco Rg. Fch Excu A. Calc. Mmoy Acc Wi Back 361 haza.29 Bach Dlay ow 1 clock cycl ucio Fch. Dco Rg. Fch Excu A. Calc. Mmoy Acc Wi Back 361 haza.30 15

16 pio 2: Dfi Bach a Dlay Wo ca, SW i NP io bach lay Wh g iucio o fill bach lay lo? Bfo bach iucio Fom h ag a: oly valuabl wh bach Fom fall hough: oly valuabl wh o bach Compil ffciv fo igl bach lay lo: Fill abou 60% of bach lay lo Abou 80% of iucio xcu i bach lay lo uful i compuaio abou 50% (60% x 80%) of lo ufully fill 361 haza.31 Wh i pipliig ha? up: 5 iucio xcuig i 5 ag pipli How o op h pipli? Ra? Who cau h iup? Sag Poblm iup occuig F Pag faul o iucio fch; mialig mmoy acc; mmoy-pocio violaio D Ufi o illgal opco EX Aihmic iup MEM Pag faul o aa fch; mialig mmoy acc; mmoy-pocio violaio 361 haza.32 16

17 Wh i pipliig ha? Complx Aig Mo a ucio A mo: Auoicm cau gi chag uig iucio xcuio up? Now woy abou wi haza ic wi o log la ag - Wi Af Ra (WAR): Wi occu bfo ip a - Wi Af Wi (WAW): Wi occu i wog o, lavig wog ul i gi - (Pviou aa haza call RAW, fo Ra Af Wi) Mmoy-mmoy Mov iucio Mulipl pag faul mak pog? 361 haza.33 Wh i pipliig ha? Floaig Poi: log xcuio im Alo, may pipli FP xcuio ui o ha ca iiia w iucio wihou waiig full lacy FP ucio Lacy iiaio Ra (MPS R4000) A, Subac 4 3 Muliply 8 4 Divi Squa oo Nga 2 1 Abolu valu 2 1 FP compa 3 2 Divi, Squa Roo ak -10X o -30X log ha A Excpio? A WAR a WAW haza ic pipli a o log am lgh 361 haza.34 17

18 Haza Dcio Suppo iucio i i abou o b iu a a pco iucio j i i h iucio pipli. Rg ( i ) = Rgi a by iucio i Wg ( i ) = Rgi wi by iucio i A RAW haza xi o gi ρ if ρ, ρ Rg( i ) Wg( j ) Kp a co of pig wi (fo i' i h pip) a compa wih opa g of cu iucio. Wh iucio iu, v i ul gi. Wh o opaio compl, mov i wi vaio. A WAW haza xi o gi ρ if ρ, ρ Wg( i ) Wg( j ) A WAR haza xi o gi ρ if ρ, ρ Wg( i ) Rg( j ) 361 haza.35 Avoiig Daa Haza by Dig Suppo iucio a xcu i a pipli fahio uch ha ucio a iiia i o. WAW avoiac: if wi o a paicula ouc (.g., g) a pfom i h am ag fo all iucio, h o WAW haza occu. poof: wi a i h am im quc a iucio. R/D E W R/D E W R/D E W WAR avoiac: if i all iucio a of a ouc occu a a ali ag ha wi o ha ouc occu i ay iucio, h o WAR haza occu. poof: A ucco iucio mu iu la, hc i will pfom wi oly af all a fo h cu iucio. 361 haza.36 18

19 Fi Gaio RSC Pipli All iucio follow am pipli o ( aic chul ). Rgi wi i la ag Avoi WAW haza All gi a pfom i fi ag af iu. Avoi WAR haza Mmoy acc i ag 4 Avoi all mmoy haza Cool haza olv by lay bach (wih fa pah) RAW haza olv by bypa, xcp o loa ul which a olv by fia (lay loa). Subaial pipliig wih vy lil co o complxiy. Machi ogaizaio i (lighly) xpo! Rli vy havily o "hi aumpio"of mmoy acc i cach 361 haza.37 Rviw: Summay of Pipliig Baic Sp Up Š Pipli Dph; if ial CP i 1, h: Spup= Pipli ph "Clock cycl upipli 1+Pipli all cycl p iucio Clock cycl pipli Haza limi pfomac o compu: ucual: mo HW ouc aa: fowaig, compil chulig cool: aly valuaio & PC, lay bach, picio caig lgh of pip ica impac of haza ic pipliig hlp iucio bawih, o lacy Compil ky o ucig co of aa a cool haza loa lay lo bach lay lo Excpio, ucio S, FP mak pipliig ha Log pipli => Bach picio, mo iucio paalllim? 361 haza.38 19