Agenda. Single Cycle Performance Assume >me for ac>ons are 100ps for register read or write; 200ps for other events. Review: Single- cycle Processor

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1 Agna CS 61C: Gat Ia in Comput Achitctu (Machin Stuctu) Intuc>on Lvl Paalllim Intucto: Rany H. Katz Davi A. PaJon hjp://int.c.bkly.u/~c61c/fa1 Rviw Piplin Excu>on Piplin Datapath Aminitivia Piplin Haza P Intuc>on Summay 11/3/1 Fall Lctu # /3/1 Fall Lctu #27 2 Rviw: Singl- cycl Poco Fiv tp to ign a poco: 1. Analyz intuc>on t Poco atapath quimnt Contol 2. Slct t of atapath Mmoy componnt & tablih Datapath clock mthoology 3. Ambl atapath m>ng th quimnt 4. Analyz implmnta>on of ach intuc>on to tmin \ng of contol point that ffct th git tanf. 5. Ambl th contol logic Fomulat Logic Equa>on Dign Cicuit 11/3/1 Fall Lctu #27 3 Input utput Singl Cycl Pfomanc Aum >m fo ac>on a 1p fo git a o wit; 2p fo oth vnt Clock at i? Int Fall 11/3/ Lctu #27 Int ftch it a op Mmoy acc it wit Total tim lw 2p 1 p 2p 2p 1 p 8p w 2p 1 p 2p 2p 7p R-fomat 2p 1 p 2p 1 p 6p bq 2p 1 p 2p 5p What can w o to impov clock at? Will thi impov pfomanc a wll? Want inca clock at to man fat pogam 4 1

2 GoJa Do Launy Ann, Bian, Cathy, Dav ach hav on loa of cloth to wah, y, fol, an put away Wah tak 3 minut Dy tak 3 minut Fol tak 3 minut Stah tak 3 minut to put cloth into aw A B C D T a k A B C D Squn>al Launy 6 PM AM Tim Squn>al launy tak 8 hou fo 4 loa Piplin Launy Piplining Lon (1/2) T a k 6 PM AM A B C D Piplin launy tak 3.5 hou fo 4 loa! Tim T a k 6 PM A B C D Tim Piplining on t hlp latncy of ingl tak, it hlp thoughput of n> wokloa Mul>pl tak opa>ng imultanouly uing iffnt ouc Potn>al pup = Numb pip tag Tim to fill piplin an >m to ain it uc pup: 2.3X v. 4X in thi xampl 2

3 T a k 6 PM A B C D Piplining Lon (2/2) Tim Suppo nw Wah tak 2 minut, nw Stah tak 2 minut. How much fat i piplin? Piplin at limit by lowt piplin tag Unbalanc lngth of pip tag uc pup 31 Singl Cycl Datapath op t immiat Data Mmoy {R[] + SignExt[imm16]} = R[t] Dt= R buw npc_l= 1 clk Rw Rt W= R Rt imm16 Ra Rb Fil 16 clk Extp= Extn bua bub 16 int ftch unit R Rt R Imm16 zo ct= Mmto= 1 Sc= Intuc>on<31:> <21:25> = Data In clk <16:2> MmW= <11:15> WEn A <:15> Data Mmoy 11/3/1 Fall Lctu # Stp in Excu>ng MIPS 1) IFtch: Intuc>on Ftch, Incmnt PC 2) Dc: Intuc>on Dco, Ra it 3) Exc: Mm- f: Calculat A Aith- log: Pfom pa>on 4) Mm: Loa: Ra Data fom Mmoy Sto: Wit Data to Mmoy 5) WB: Wit Data Back to it PC Rawn Singl Cycl Datapath +4 intuc>on mmoy 1. Intuc>on Ftch t imm git Data mmoy 2. Dco/ it Ra 3. Excut 4. Mmoy 5. Wit Back 3

4 Piplin git Mo Dtail Piplin PC intuc>on mmoy t git Data mmoy +4 imm 1. Intuc>on Ftch 2. Dco/ it Ra 3. Excut 4. Mmoy 5. Wit Back N git btwn tag To hol infoma>on pouc in pviou cycl Chapt 4 Th Poco 14 IF fo Loa, Sto, ID fo Loa, Sto, Chapt 4 Th Poco 15 Chapt 4 Th Poco 16 4

5 EX fo Loa MEM fo Loa Chapt 4 Th Poco 17 Chapt 4 Th Poco 18 WB fo Loa Coct Datapath fo Loa Wong git numb Chapt 4 Th Poco 19 Chapt 4 Th Poco 2 5

6 Rviw Piplin Excu>on Piplin Datapath Aminitivia Piplin Haza P Intuc>on Summay Agna Why both t an a MIPS wit g? op t hamt funct N to hav 2 pat immiat if 2 ouc an 1 >na>on alway in am plac bit 26 5 bit 21 5 bit 16 5 bit 5 bit 6 bit op t immiat 6 bit 5 bit 5 bit 16 bit 11 6 SPUR poco (1 t pojct Rany an I wok on togth) 11/3/1 Fall Lctu # /3/1 Fall Lctu #27 22 Aminitivia Pojct 3: Tha Lvl Paalllim + Data Lvl Paalllim + Cach p>miza>on Du Pat 2 u Satuay 11/13 Pojct 4: Singl Cycl Poco in Logicim Du Pat 2 u Satuay 11/27 Fac- to- Fac gaing: Signup fo >mlot lat wk Exta Cit: Fatt Vion of Pojct 3 Du Monay 11/29 Minight Final Rviw: TBD (Vot via Suvy!) Final: Mon Dc 13 8AM- 11AM (TBD) 11/3/1 Fall Lctu #27 23 Hou/wk K? avg 13, mian (4 unit = 12 hou) Sinc pick alit >m fo viw, oing to if >ll Thu bt (Mon v Thu) Suvy 11/3/1 Fall Lctu #

7 Comput in th Nw Giant win Wol Si! (4-1 ov Dalla Txa Rang) S.F. Giant uing tch to thi avantag Th PolC, MaktWatch, 1/29/1 Giant w an aly u of tch, an it look lik th invtmnt a paying off. Bill Nukom (chif Micoo} 25 ya Scout givn cama to uploa vio of popct X Spot Spotmo>on, which ou~it play with no that mau vything thy o: play vlopmnt, valuat talnt, hab a} injuy (wing chang?) Intnal SW vlopmnt tam to min ata fo cou>ng (oth tam u tana SW packag) 266 Cico Wi- Fi acc point thoughout pak; 1 t in 24 Voic ov IP to av $ intnally fo SF Giant 11/3/1 Fall Lctu #27 25 Piplin Excu>on Rpnta>on Tim IFtch Dc IFtch Dc Exc Mm WB IFtch Dc Exc Mm WB IFtch Dc Exc Mm WB IFtch Dc Exc Mm WB IFtch Dc Exc Mm WB Exc Mm WB Evy intuc>on mut tak am numb of tp, alo call piplin tag, o om will go il om>m PC Gaphical Piplin Diagam +4 intuc>on mmoy 1. Intuc>on Ftch t imm git Data mmoy 2. Dco/ it Ra 3. Excut 4. Mmoy 5. Wit Back U atapath figu blow to pnt piplin IFtch Dc Exc Mm WB D$ I n t. Gaphical Piplin Rpnta>on (In, ight half highlight a, l half wit) Tim (clock cycl) Loa A Sto Sub D$ D$ D$ D$ D$ 7

8 Piplin Pfomanc Aum >m fo tag i 1p fo git a o wit 2p fo oth tag Int What i piplin clock at? Compa piplin atapath with ingl- cycl atapath Int ftch it a op Mmoy acc it wit Total tim lw 2p 1 p 2p 2p 1 p 8p w 2p 1 p 2p 2p 7p R-fomat 2p 1 p 2p 1 p 6p bq 2p 1 p 2p 5p Piplin Pfomanc Singl- cycl (T c = 8p) Piplin (T c = 2p) Fall 11/3/ Lctu #27 29 Fall 11/3/ Lctu #27 3 Piplin Spup If all tag a balanc i.., all tak th am >m Tim btwn intuc>on piplin = Tim btwn intuc>on nonpiplin Numb of tag If not balanc, pup i l Spup u to inca thoughput Latncy (>m fo ach intuc>on) o not ca Intuc>on Lvl Paalllim (ILP) Anoth paalllim fom to go with Rqut Lvl Paalllim an Data Lvl Paalllim RLP.g., Wahou Scal Compu>ng DLP.g., SIMD, Map Ruc ILP.g., Piplin intuc>on Excu>on 5 tag piplin => 5 intuc>on xcu>ng imultanouly, on at ach piplin tag Fall 11/3/ Lctu # /3/1 Fall Lctu #27 8

9 Haza Situa>on that pvnt ta>ng th nxt intuc>on in th nxt cycl Stuctual haza A qui ouc i buy (oommat tuying) Data haza N to wait fo pviou intuc>on to complt it ata a/wit (pai of ock in iffnt loa) Contol haza Dciing on contol ac>on pn on pviou intuc>on (how much tgnt ba on how clan pio loa tun out) Stuctual Haza Conflict fo u of a ouc In MIPS piplin with a ingl mmoy Loa/to qui ata acc Intuc>on ftch woul hav to tall fo that cycl Woul cau a piplin bubbl Hnc, piplin atapath qui paat intuc>on/ata mmoi Rally paat L1 intuc>on cach an L1 ata cach Fall 11/3/ Lctu #27 33 Fall 11/3/ Lctu #27 34 I n t. Stuctual Haza #1: Singl Mmoy Loa Int 1 Int 2 Int 3 Int 4 Tim (clock cycl) D$ D$ Ra am mmoy twic in am clock cycl D$ D$ D$ I n t. Stuctual Haza #2: it (1/2) w Int 1 Int 2 Int 3 Int 4 Tim (clock cycl) D$ D$ Can w a an wit to git imultanouly? D$ D$ D$ 9

Stuctual Haza #2: it (2/2) Two iffnt olu>on hav bn u:

to it uing fit half of ach clock cycl Ra fom it uing

wit pot Rult: can pfom Ra an Wit uing am clock cycl

pviou intuc>on a $, $t, $t1 ub $t2, $, $t3 Fall 11/3/1

comput Don t wait fo it to b to in a git Rqui xta

avoi tall by fowaing If valu not comput whn n Can t

10 Stuctual Haza #2: it (2/2) Two iffnt olu>on hav bn u: 1) Fil acc i VERY fat: tak l than half th >m of tag Wit to it uing fit half of ach clock cycl Ra fom it uing con half of ach clock cycl 2) Buil Fil with inpnnt a an wit pot Rult: can pfom Ra an Wit uing am clock cycl Data Haza An intuc>on pn on compl>on of ata acc by a pviou intuc>on a $, $t, $t1 ub $t2, $, $t3 Fall 11/3/ Lctu #27 38 Fowaing (aka Bypaing) U ult whn it i comput Don t wait fo it to b to in a git Rqui xta connc>on in th atapath Loa- U Data Haza Can t alway avoi tall by fowaing If valu not comput whn n Can t fowa backwa in >m! Fall 11/3/ Lctu #27 39 Fall 11/3/ Lctu #27 4 1

11 Co Schuling to Avoi Stall Ro co to avoi u of loa ult in th nxt intuc>on C co fo A = B + E; C = B + F; tall tall lw $t1, ($t) lw $t2, 4($t) a $t3, $t1, $t2 w $t3, 12($t) lw $t4, 8($t) a $t5, $t1, $t4 w $t5, 16($t) 13 cycl lw $t1, ($t) lw $t2, 4($t) lw $t4, 8($t) a $t3, $t1, $t2 w $t3, 12($t) a $t5, $t1, $t4 w $t5, 16($t) 11 cycl I. Thank to piplining, I hav uc th tim it took m to wah my on hit. II. Long piplin a alway a win (inc l wok p tag & a fat clock). A)() P Intuc>on I i Tu an II i Tu B)(oang) I i Fal an II i Tu C)(gn) I i Tu an II i Fal Fall 11/3/ Lctu #27 41 Th BIG Pictu Piplin Summay Piplining impov pfomanc by incaing intuc>on thoughput: xploit ILP Excut mul>pl intuc>on in paalll Each intuc>on ha th am latncy Subjct to haza Stuctu, ata, contol Fall 11/3/ Lctu #

Instruction Execution

Instruction Execution MIPS Piplining Cpt280 D Cuti Nlon Intuction Excution C intuction: x = a + b; Ambly intuction: a a,b,x Stp 1: Stp 2: Stp 3: Stp : Stp 5: Stp 6: Ftch th intuction Dtmin it i an a intuction Ftch th ata a