CS152 Computer Architecture and Engineering Lecture 12. Exceptions (continued) Introduction to Pipelining

Transcription

1 CS152 Compu Achicu a Egiig Lcu 12 Excpio (coiu) oucio o Pipliig cob 12 h, 2001 Joh Kubiaowicz (hp.c.bkly.u/~kubio) lcu li: hp://www-i.c.bkly.u/~c152/ Rcap: Micopogammig Micopogammig i a covi mho fo implmig ucu cool a iagam: Raom logic plac by micopc quc a RM Each li of RM call a Piucio: coai quc cool + valu fo cool poi limi a aiio: bach o zo, x quial, bach o Piucio a fom iplach RM Hoizoal PCo: o cool bi i Pucio fo vy cool li i aapah Vical PCo: goup of cool-li co ogh i Pucio (.g. poibl ) Cool ig uc o Micopogammig Pa of h ig poc i o vlop a laguag ha cib cool a i ay fo huma o ua Lc12.1 Lc12.2 Rcap: Micopogammig Excpio mico-pc pco quc cool aapah cool micoiucio (µ) µ-quc: fch,ipach, quial Dipach RM Dco To DaaPah Micopogammig i a fuamal cocp implm a iucio by builig a vy impl poco a ipig h iucio ial fo vy complx iucio a wh fw gi af a poibl ovkill wh SA mach aapah 1-1 Dco µ-co RM Dco implm ou P-co laguag: Fo iac: - - mm- Lc12.3 u pogam Excpio: omal cool flow: quial, jump, bach, call, u Excpio = upogamm cool af ym ak acio o hal h xcpio - mu co h a of h offig iucio - co ay oh ifomaio cay o u afwa u cool o u mu av & o u a Allow coucio of a u viual machi Sym Excpio Hal u fom xcpio Lc12.4

2 Two Typ of Excpio: up a Tap up cau by xal v: - Nwok, Kyboa, Dik /, Tim aychoou o pogam xcuio - Mo iup ca b iabl fo bif pio of im - Som (lik Pow Failig ) a o-makabl (NM) may b hal bw iucio imply up a um u pogam Tap cau by ial v - xcpioal coiio (ovflow) - o (paiy) - faul (o-i pag) ychoou o pogam xcuio coiio mu b mi by h hal iucio may b i o imula a pogam coiu o pogam may b abo Lc12.5 Pci up Pci Ÿ a of h machi i pv a if pogam xcu up o h offig iucio All pviou iucio compl ffig iucio a all followig iucio ac a if hy hav o v a Sam ym co will wok o iff implmaio Poiio claly ablih by BM Difficul i h pc of pipliig, ou-o-o xcuio,... MPS ak hi poiio mpci Ÿ ym ofwa ha o figu ou wha i wh a pu i all back ogh Pfomac goal of la ig o foak pci iup ym ofwa vlop, u, mak c. uually wih hy ha o o hi Mo chiqu fo ou-of-o xcuio a bach picio hlp implm pci iup Lc12.6 Big Picu: u / ym mo By poviig wo mo of xcuio (u/ym) i i poibl fo h compu o maag ilf opaig ym i a pcial pogam ha u i h pivilg mo a ha acc o all of h ouc of h compu p viual ouc o ach u ha a mo covi ha h phyical ouc - fil v. ik co - viual mmoy v phyical mmoy poc ach u pogam fom oh poc ym fom maliciou u. S i aum o kow b, a i u co, o ym mo o xcpio. Excpio allow h ym o ak acio i po o v ha occu whil u pogam i xcuig: Aig h Excpio Hal Taiioal Appoach: up Vco PC <- MEM[ V_ba + cau 00] 370, 68000, Vax, 80x86,... iv_ba RSC Hal Tabl PC < T_ba + cau 0000 av a a jump Spac, PA, M88K,... MPS Appoach: fix y PC < EXC_a Acually vy mall abl - RESET y Migh povi upplmal bhavio (alig wih omal floaig-poi umb fo iac). - TLB Uimplm iucio u o mula iucio ha - oh 10/12/01 w o iclu i hawa UCB Fall ( MicoVax) Lc12.7 iv_ba cau hal co hal y co cau Lc12.8

3 Savig Sa Puh i oo h ack Vax, 68k, 80x86 Shaow Rgi M88k Sav a i a haow of h ial pipli gi Sav i i pcial gi MPS EPC, BaVa, Sau, Cau Aiio o MPS SA o uppo Excpio? Excpio a i kp i copoco 0. U mfc0 a co of h gi Evy gi i bi, bu may b oly paially fi BaVA (gi 8) gi coai mmoy a a which mmoy fc occu Sau (gi 12) iup mak a abl bi Cau (gi 13) h cau of h xcpio Bi 5 o 2 of hi gi co h xcpio yp (.g ufi iucio=10 a aihmic ovflow=12) EPC (gi 14) a of h affc iucio (gi 14 of copoco 0). Cool igal o wi BaVA, Sau, Cau, a EPC B abl o wi xcpio a io PC ( hx ) May hav o uo PC = PC + 4, ic wa EPC o poi o offig iucio (o i ucco): PC = PC - 4 Lc12.9 Lc12.10 Dail of Sau gi Sau Mak = 1 bi fo ach of 5 hawa a 3 ofwa iup lvl 1 => abl iup 0 => iabl iup k = kl/u 0 => wa i h kl wh iup occu 1 => wa uig u mo = iup abl 0 => iup w iabl 1 => iup w abl Wh iup occu, 6 LSB hif lf 2 bi, ig 2 LSB o 0 u i kl mo wih iup iabl Mak k k k ol pv cu Lc12.11 Dail of Cau gi Sau Pig Pig iup 5 hawa lvl: bi if iup occu bu o y vic hal ca wh mo ha o iup occu a am im, o whil co iup qu wh iup iabl Excpio Co co ao fo iup 0 (NT) => xal iup 4 (ADDRL) => a o xcpio (loa o i fch) 5 (ADDRS) => a o xcpio (o) 6 (BUS) => bu o o iucio fch 7 (DBUS) => bu o o aa fch 8 (Sycall) => Sycall xcpio 9 (BKPT) => Bakpoi xcpio 10 (R) => Rv ucio xcpio 12 (VF) => Aihmic ovflow xcpio 5 2 Co Lc12.12

4 Pa of h hal i ap_hal..kx 0x y: Excpio/iup com h. oa mov $k1 $a # Sav $a. a w $v0 1 # No - a w ca u $p w $a0 2 mfc0 $k0 $13 # Cau Gab h cau gi li $v0 4 # ycall 4 (pi_) la $a0 m1_ ycall li $v0 1 # ycall 1 (pi_i) l $a0 $k0 2 # hif Cau g ycall : lw $v0 1 lw $a0 2 mfc0 $k0 $14 # EPC G h u a (EPC). oa mov $a $k1 # Ro $a. a f # Ru fom xcpio hal aiu $k0 $k0 4 # Ru o x iucio j $k0 Lc12.13 Exampl: How Cool Hal Tap i ou FSD Ufi ucio c wh o x a i fi fom a 1 fo h op valu. W hal hi xcpio by fiig h x a valu fo all op valu oh ha lw, w, 0 (R-yp), jmp, bq, a oi a w a 12. Show ymbolically uig oh o iica ha h op fil o o mach ay of h opco ha labl ac ou of a 1. Aihmic ovflow c o op uch a ig a U o av PC a xcpio hal Exal up flagg by a iup li Agai, mu av PC a xcpio hal No: Challg i igig cool of a al machi i o hal iff iacio bw iucio a oh xcpio-cauig v uch ha cool logic mai mall a fa. Complx iacio mak h cool ui h mo challgig apc of hawa ig Lc12.14 How a ap a iup o a iagam? R[] <= S 0101 iucio fch R <= MEM[PC] PC <= PC R[] <= S 0111 M <= MEM[S] 1001 R[] <= M 1010 co EPC <= PC - 4 S<= PC +SX PC <= xp_a EPC <= PC oh cau <= 12 (vf) PC <= xp_a cau <= 10 (R) R-yp Ri LW BEQ ovflow SW S <= A f -A B= B S <= A fu B S <= A op ZX S <= A + SX S <= A + SX h PC <= S MEM[S] <= B 1100 Pig NT EPC <= PC - 4 PC <= xp_a cau <= 0(NT) Hal up ufi iucio Lc12.15 Bu: Wha ha o chag i ou P-quc? N cocp of bach a mico-co lvl µ-off 4? 1 Do µ-bach Co Slc N? 1 0 pig iup ovflow A micopc Dipach RM pco Sq Slc EPC <= PC - 4 PC <= xp_a cau <= 12 (vf) ovflow R-yp S <= A fu B 0100 µa Slc Logic Lc12.16

5 Exampl: Ca aily u wih fo o-ial mmoy R-yp S <= A fu B R[] <= S PC <= PC + 4 Ri S <= A o ZX R[] <= S PC <= PC + 4 R <= MEM[PC] ~wai A <= R[] B <= R[] LW S <= A + SX M <= MEM[S] ~wai wai R[] <= M PC <= PC + 4 iucio fch wai co / opa fch SW BEQ PC <= S <= A + SX Nx(PC) MEM[S] <= B ~wai PC <= PC + 4 wai Excu Mmoy Wi-back Lc12.17 Amiiaiv u Mim : No ga y! Soy! G a aig Chap 6 Compl chap o Pipliig... Scio: Moay (10/15) cio Ÿ Coy You will moa you poco o a myy pogam - Rpo ill u a miigh Followig wk Ÿ Uual plac Lab Rpo: Up o you o o a goo job of ummaizig you wok Pa of ga will b o qualiy of you wiig - Pu co a chmaic i appic appopialy fc - U acual wopoco (Micoof Wo oli) Lc12.18 Quio #1: Why o micocoig? f impl iucio coul xcu a vy high clock a f you coul v wi compil o pouc micoiucio f mo pogam u impl iucio a aig mo f micoco i kp i RAM ia of RM o a o fix bug f am mmoy u fo cool mmoy coul b u ia a cach fo macoiucio Th why o kip iucio ipaio by a micopogam a imply compil icly io low laguag of machi? (micopogammig i ovkill wh SA mach aapah 1-1) Rcall: Pfomac Evaluaio Wha i h avag CP? a iagam giv CP fo ach iucio yp wokloa giv fqucy of ach yp Typ CP i fo yp Fqucy CP i x fq i Aih/Logic 4 40% 1.6 Loa 5 30% 1.5 So 4 10% 0.4 bach 3 20% 0.6 Avag CP:4.1 Lc12.19 Lc12.20

6 Quio #2: Ca w g CP < 4.1? Sm o b lo of il hawa Why o ovlap iucio??? PCW PCWCo PCSc Zo od MmW RW RgD RgW SlA 1 PC 0 0 R Zo 0 Ra RA 5 R Rb bua A 1 al 0 5 Rg Fil 1 Mmoy R 4 0 WA Rw B Di Dou R 1 buw bub << 2 Cool ucio Rg Mm Daa Rg u Th Big Picu: Wh a W Now? Th Fiv Claic Compo of a Compu Nx Topic: Poco pu Cool Mmoy Daapah upu Pipliig by Aalogy Pipli haza mm Ex 16 Exp MmoRg p SlB Lc12.21 Lc12.22 Pipliig i Naual! Lauy Exampl A, Bia, Cahy, Dav ach hav o loa of cloh o wah, y, a fol Wah ak 30 miu Dy ak 40 miu Fol ak 20 miu A B C D Lc12.23 T a k Squial Lauy A B C D 6 PM Miigh Tim Squial lauy ak 6 hou fo 4 loa f hy la pipliig, how log woul lauy ak? Lc12.24

7 T a k Pipli Lauy: Sa wok ASAP A B C D 6 PM Miigh Tim Pipli lauy ak 3.5 hou fo 4 loa Lc12.25 T a k Pipliig Lo A B C D 6 PM Tim Pipliig o hlp lacy of igl ak, i hlp houghpu of i wokloa Pipli a limi by low pipli ag Mulipl ak opaig imulaouly uig iff ouc Poial pup = Numb pip ag Ubalac lgh of pip ag uc pup Tim o fill pipli a im o ai i uc pup Sall fo Dpc Lc12.26 Th Fiv Sag of Loa Loa Cycl 1 Cycl 2 Cycl 3 Cycl 4 Cycl 5 fch Rg/Dc Exc Mm W fch: ucio Fch Fch h iucio fom h ucio Mmoy Rg/Dc: Rgi Fch a ucio Dco Exc: Calcula h mmoy a Mm: Ra h aa fom h Daa Mmoy W: Wi h aa back o h gi fil Lc12.27 Dco Fch No: Th 5 ag w h all alog! Excu Mmoy Wi-back R-yp ou <= A fu B 0100 R[] <= ou 0101 Ri ou <= A op ZX 0110 R[] <= ou 0111 R <= MEM[PC] PC <= PC ou <= PC +SX 0001 LW ou <= A + SX 1000 M <= MEM[ou] 1001 R[] <= M 1010 SW ou <= A + SX 1011 MEM[ou] <= B 1100 BEQ f A = B h PC <= ou 0010 Lc12.28

8 Pipliig mpov pfomac by icaig houghpu Baic a al pup i umb of ag i h pipli. Do w achiv hi? Lc12.29 Wha o w o a o pli h aapah io ag? Lc12.30 Gaphically Rpig Pipli Covioal Pipli Excuio Rpaio Tim Fch Dc Exc Mm WB Fch Dc Exc Mm WB Fch Dc Exc Mm WB Fch Dc Exc Mm WB Ca hlp wih awig quio lik: how may cycl o i ak o xcu hi co? wha i h oig uig cycl 4? u hi paio o hlp ua aapah Pogam Flow Fch Dc Exc Mm WB Fch Dc Exc Mm WB Lc12.31 Lc12.

9 Sigl Cycl, Mulipl Cycl, v. Pipli Cycl 1 Cycl 2 Clk Sigl Cycl mplmaio: Loa So Wa Cycl 1 Cycl 2 Cycl 3 Cycl 4 Cycl 5 Cycl 6 Cycl 7 Cycl 8 Cycl 9 Cycl 10 Clk Mulipl Cycl mplmaio: Loa So R-yp fch Rg Exc Mm W fch Rg Exc Mm fch Why Pipli? Suppo w xcu 100 iucio Sigl Cycl Machi 45 /cycl x 1 CP x 100 i = 4500 Mulicycl Machi 10 /cycl x 4.6 CP (u o i mix) x 100 i = 4600 al pipli machi 10 /cycl x (1 CP x 100 i + 4 cycl ai) = 1040 Pipli mplmaio: Loa fch Rg Exc Mm W So fch Rg Exc Mm W R-yp fch Rg Exc Mm W Lc12.33 Lc Why Pipli? Bcau w ca! Tim (clock cycl) Lc12.35 Ca pipliig g u io oubl? Y: Pipli Haza ucual haza: amp o u h am ouc wo iff way a h am im - E.g., combi wah/y woul b a ucual haza o fol buy oig omhig l (wachig TV) cool haza: amp o mak a ciio bfo coiio i valua - E.g., wahig fooball uifom a o g pop g lvl; o af y bfo x loa i - bach iucio aa haza: amp o u im bfo i i ay - E.g., o ock of pai i y a o i wah; ca fol uil g ock fom wah hough y - iucio p o ul of pio iucio ill i h pipli Ca alway olv haza by waiig pipli cool mu c h haza ak acio (o lay acio) o olv haza Lc12.36

10 Sigl Mmoy i a Sucual Haza Sucual Haza limi pfomac. Loa Tim (clock cycl) Mm Rg Mm Rg Mm Rg Mm Rg Mm Mm Rg Mm Rg Rg Mm Rg Mm Rg Mm Rg Exampl: if 1.3 mmoy acc p iucio a oly o mmoy acc p cycl h avag CP 1.3 ohwi ouc i mo ha 100% uiliz Dcio i ay i hi ca! (igh half highligh ma a, lf half wi) Lc12.37 Lc Cool Haza Soluio #1: Sall A Bq Loa Tim (clock cycl) Mm Rg Mm Rg Sall: wai uil ciio i cla mpac: 2 lo cycl (i.. 3 clock cycl p bach iucio) => low Mov ciio o of co av 1 cycl p bach Mm Rg Mm Rg Lo poial Mm Rg Mm Rg Lc Cool Haza Soluio #2: Pic A Bq Loa Tim (clock cycl) Mm Rg Mm Rg Mm Rg Mm Rg Mm Pic: gu o icio h back up if wog mpac: 0 lo cycl p bach iucio if igh, 1 if wog (igh - 50% of im) N o Squah a a followig iucio if wog Pouc CP o bach of (1 * *.5) = 1.5 Toal CP migh h b: 1.5 * *.8 = 1.1 (20% bach) Mo yamic chm: hioy of 1 bach (- 90%) Rg Mm Rg Lc12.40

11 Cool Haza Soluio #3: Dlay Bach Daa Haza o 1. A Bq Mic Loa Tim (clock cycl) Mm Rg Mm Rg Mm Rg Mm Rg Mm Dlay Bach: Rfi bach bhavio (ak plac af x iucio) mpac: 0 clock cycl p bach iucio if ca fi iucio o pu i lo (- 50% of im) A lauch mo iucio p clock cycl, l uful Rg Mm Rg Mm Rg Mm Rg Lc12.41 a 1,2,3 ub 4,1,3 a 6,1,7 o 8,1,9 xo 10,1,11 Lc12.42 Daa Haza o 1: Dpci backwa i im a haza Daa Haza Soluio: Fowa ul fom o ag o aoh. Tim (clock cycl) 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. Tim (clock cycl) 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 Lc12.43 o K if fi a/wi poply Lc12.44

12 Fowaig (o Bypaig): Wha abou Loa? Dpci backwa i im a haza Tim (clock cycl) F D/RF EX MEM WB lw 1,0(2) m Rg Dm Rg Fowaig (o Bypaig): Wha abou Loa Dpci backwa i im a haza Tim (clock cycl) F D/RF EX MEM WB lw 1,0(2) m Rg Dm Rg ub 4,1,3 ub 4,1,3 Sall Ca olv wih fowaig: Mu lay/all iucio p o loa Ca olv wih fowaig: Mu lay/all iucio p o loa Lc12.45 Lc12.46 Digig a Pipli Poco Cool a Daapah: Spli a iag io 5 pic Go back a xami you aapah a cool iagam aocia ouc wih a R <- Mm[PC]; PC < PC+4; A <- R[]; B< R[] u ha flow o o coflic, o figu ou how o olv S < A + B; S < A o ZX; S < A + SX; S < A + SX; f Co PC < PC+SX; a cool i appopia ag M < Mm[S] Mm[S] <- B R[] < S; R[] < S; R[] < M; Equal Lc12.47 Nx PC PC. Mm R Rg Fil A B Exc S D Mm Acc M Daa Mm Rg. Fil Lc12.48

13 Summay: Pipliig Ruc CP by ovlappig may iucio Avag houghpu of appoximaly 1 CP wih fa clock Uiliz capabilii of h Daapah a x iucio whil wokig o h cu o limi by lgh of log ag (plu fill/fluh) c a olv haza Wha mak i ay all iucio a h am lgh ju a fw iucio foma mmoy opa appa oly i loa a o Wha mak i ha? ucual haza: uppo w ha oly o mmoy cool haza: o woy abou bach iucio aa haza: a iucio p o a pviou iucio Summay Micopogammig i a fuamal cocp implm a iucio by builig a vy impl poco a ipig h iucio ial fo vy complx iucio a wh fw gi af a poibl Cool ig uc o Micopogammig Excpio a h ha pa of cool N o fi covi plac o c xcpio a o bach o a o micoiucio ha av PC a ivok h opaig ym Poviig cla iup mol g ha wih pipliig! Pci ExcpioŸ a of h machi i pv a if pogam xcu up o h offig iucio All pviou iucio compl ffig iucio a all followig iucio ac a if hy hav o v a Lc12.49 Lc12.50 Summay: Wh hi cla i goig W ll buil a impl pipli a look a h iu Lab 5 Ÿ Pipli Poco Lab 6 Ÿ Wih cach W ll alk abou mo poco a wha ally ha: xcpio halig yig o impov pfomac wih ou-of-o xcuio, c. Tyig o g CP < 1 (Supcala xcuio) Lc12.51