abstract models of noc-based mpsocs for design space exploration

More documents

Recommendations

Info

for!the!sake!of!simplicity!and!efficiency.!However,!in!the!abstract!model,!such!procedures!must!be! implemented!separately!in!order!to!simplify!the!design!space!exploration!(e.g.!to!investigate!the! positive!and!negative!impacts!of!using!adaptive!routing).! ! ! analyze interactions NoC RTL model actor-oriented NoC model Optimized NoC RTL model complex testbenches debbugging / analysis tools design space exploration, validation Figure!17!!S!Adopted!approach!for!NoC!modeling!and!design!space!exploration.! Additionally,! the! specification! of! the! system! in! interactions! can! abstract! the! notion! of! discrete! time! that! exists! in! the! RTL! model,! providing! just! a! partial! order! of! the! communication! among!model!components.!Such!abstract!model!can!be!used!to!show!the!system!functionality!or! be! annotated! with! actual! timing! information! so! that! a! more! accurate! timing! behavior! can! be! reflected.!! In! this! context,! two! UML! sequence! diagrams,! which! describe! the! interactions! of! the! HERMES!router!components,!were!defined!as!illustrated!in!Figure!18.!The!UML!sequence!diagram,! shown! in! Figure! 18! (a),! refers! to! the! arbitration! request! by! a! particular! input! buffer! and! the! establishment!of!a!connection!between!it!and!an!output!port.!! InputBuffer:b1 requestArbitration(flit) alt 1 8 [free] arbitration granted [else] arbitration NOT granted 9 Controller 2 requestArbitration(flit) 5 7 Arbiter Router OutputPort 3 requestRouting(flit) 4 isFree() boolean:free setFree(false) 6 InputBuffer:b1 alt sendFlit(flit) response [response = true] eraseFlit(flit) Controller alt sendFlit(flit) response [response = true AND flit IS sizeFlit] getPacketSize() [response = true AND flit IS payloadFlit] alt [packetSize = 0] decreasePacketSize() setFree(true) Output Port sendFlit(flit) InputBuffer:b2 (a)! (b)! Figure!18!S!UML!sequence!diagrams!depicting!interactions!between!components!of!the!HERMES!NoC.! Figure!extended!from![IND08].! Initially,!the!input!buffer!sends!the!packet!header!to!the!routing!controller!(interaction!1).! The!routing!controller!asks!the!arbiter!to!choose!one!of!the!possible!incoming!requests!that!can! 1 2 4 5 3 51
52 arrive!from!any!of!the!five!input!buffers!(interaction!2).!After!selecting!an!incoming!input!buffer! request,!the!arbiter!sends!the!header!flit!to!the!router!(interaction!3)!that!executes!a!particular! algorithm!(for!instance,!XY!algorithm)!to!determine!which!output!port!the!packet!should!be!sent! to.!Once!the!routing!is!done!(interactions!4!and!5),!the!controller!verifies!if!the!chosen!output!port! is! free! (interaction! 6).! If! the! output! port! is! free! (interaction! 7),! the! input! buffer! establishes! the! connection!to!the!output!port!(interaction!8),!otherwise!the!connection!is!refused!(interaction!9)! and!the!input!buffer!must!start!the!whole!inputSoutput!connection!requesting!process!again.! ! The!second!UML!sequence!diagram!shown!in!Figure!18!(b),!identifies!the!transmission!of!a! flit!from!an!input!buffer!to!a!neighbor!router!through!an!output!channel.!Initially,!the!controller! receives! the! flit! from! the! local! input! buffer! (interaction! 1)! and! checks! which! output! port! is! allocated! to! it! (interaction! 2).! After! sending! the! flit! (interaction! 3),! the! controller! waits! for! acknowledgement!(interaction!4).!A!positive!acknowledgement!removes!the!successfully!sent!flit! from! the! source! input! buffer! (interaction! 5),! while! a! negative! acknowledgement! causes! a! retransmission!of!the!flit.! It! is! important! to! mention! that! both! UML! sequence! diagrams! consider! timing! among! interactions,!which!were!extracted!from!the!simulation!of!the!HERMES!RTL!model.!The!RENATO! actorSoriented! model! was! implemented! using! Ptolemy! II,! following! the! interaction! descriptions! shown! in! Figure! 18.! RENATO! comprises! two! main! actors:! input! buffer! for! temporary! storage! of! packet/flits!and!arbiter.!Due!to!the!modeling!flexibility,!each!RENATO's!packet!flit!is!modeled!as!a! record!token,!as!illustrated!in!Figure!19.!! Typical packet structure TRAILER PAYLOAD HEADER source_y source_x timestamp_sent HERMES’ header flit y x RENATO’s header flit (record token representation) timestamp_ini payload where: x // x target address y // y target address size // packet size (number of flits) payload // data timestamp_ini // initial packet timestamp timestamp_sent // timestamp time that the packet is being sent source_x source_y // source x address // source y address evaluation parameters Figure!19!!S!Example!of!packet!flit!difference!between!HERMES!and!RENATO!models.! The!use!of!record!token!increases!the!range!of!evaluation!parameters!(e.g.!timestamp!time! that! the! packet! is! sent)! that! can! be! included! and! considered! without! requiring! large! code! rewriting,!for!instance!the!modification!of!state!machines!as!in!RTL!approach.!! The!arbiter!implements!centralized!roundSrobin!arbitration!(code!illustrated!in!Figure!20)! that!grants!the!access!to!incoming!packets.!The!priority!of!an!input!port!is!a!function!of!the!last! size y x
Page 1: ! PONTIFÍCIA UNIVERSIDADE CATÓLIC
Page 7 and 8: ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !
Page 9 and 10: ! ABSTRACT MODELS OF NOC-BASED MPSO
Page 11 and 12: Figure 34 - (a) Example of an appli
Page 13 and 14: ! LIST OF ABBREVIATIONS APD! Averag
Page 15: 5.! MODELNBASED!DESIGN!FLOW!FOR!NOC
Page 18 and 19: est!placement!for!the!application!t
Page 20 and 21: ! 2. !!!a!technique!that!can!be!app
Page 22 and 23: ! 23
Page 24 and 25: modeling,!as!proposed!in![KIE99],!i
Page 26 and 27: ! Director 1 input ports Composite
Page 28 and 29: 2.2.2.1 Initialization ! The! initi
Page 30 and 31: ! ! 31
Page 32 and 33: flow![BER05].! ! Kogel!et!al.![KOG0
Page 34 and 35: ! One! contribution! of! the! propo
Page 36 and 37: ! Figure!11!-!Example!of!a!CDCG.!Fi
Page 38 and 39: using! HSPICE! and! the! Berkeley!
Page 40 and 41: and!direct!connection!links!between
Page 42 and 43: 3.3 MPSoC Application Modeling and
Page 44 and 45: already! designed.! Software! can!
Page 46 and 47: ! ! ! ! ! ! 47
Page 48 and 49: ! IP ' NI Router ' IP ' NI Router '
Page 52 and 53: input! port! having! a! routing! re
Page 54 and 55: [OST08].! ! ptrt hft + pcksize * ct
Page 56 and 57: accuracy!on!blocking!other!packets.
Page 58 and 59: NoC generation 1 Traffic Generation
Page 60 and 61: eference!model!(according!to!the!av
Page 62 and 63: packets)! in! average.! In! this! s
Page 64 and 65: ate! inside! a! given! sample! peri
Page 66 and 67: presents!such!a!small!difference!to
Page 68 and 69: and!the!switching!activity!of!its!a
Page 70 and 71: ! ! Power!model\Traffic! Uniform! N
Page 72 and 73: ! ! 73
Page 74 and 75: 8 Director 1 AB1 AB2 AB3 PE 01 AB1
Page 76 and 77: execution!of!applications!running!o
Page 78 and 79: ! Application/Modeling:!in!this!ste
Page 80 and 81: extracted!is!the!real!load!imposed!
Page 82 and 83: (a)!30%! (b)!40%! (c)!50%! Figure!3
Page 84 and 85: ! Table! XII! presents! the! maximu
Page 86 and 87: ! ! ! 87
Page 88 and 89: ! Indrusiak,!L.!S.;!Ost,!L.;!Mölle
Page 90 and 91: ! ! 91
Page 92 and 93: [BER05]! Bertozzi,! D.;! Jalabert,!
Page 94 and 95: [GUI08]! Guindani,! G.;! Reinbrecht
Page 96 and 97: ! Platforms”.!In:!IEEE!Symposium!
Page 98 and 99: [PIM01]! Pimentel,! A.D.;! Hertzber

abstract models of noc-based mpsocs for design space exploration

Create successful ePaper yourself

Delete template?

Save as template?