Lecture 9 - Åbo Akademi

More documents

Recommendations

Info

ACK/NACK flow control scheme • when flits are sent on a link, a local copy is kept in a buffer by sender • when ACK received by sender, it deletes copy of flit from its local buffer • when NACK is received, sender rewinds its output queue and starts resending flits, starting from the corrupted one • implemented either end-to-end or switch-to-switch • sender needs to have a buffer of size 2N + k • N is number of buffers encountered between source and destination • k depends on latency of logic at the sender and receiver • overall a minimum of 3N + k buffers are required • fault handling support comes at cost of greater power, area overhead
Flow control schemes • Network and Transport-Layer Flow Control • Flow Control without Resource Reservation • Technique #1: drop packets when receiver NI full • improves congestion in short term but increases it in long term • Technique #2: return packets that do not fit into receiver buffers to sender • to avoid deadlock, rejected packets must be accepted by sender • Technique #3: deflection routing • when packet cannot be accepted at receiver, it is sent back into network • packet does not go back to sender, but keeps hopping from router to router till it is accepted at receiver • Flow Control with Resource Reservation • credit-based flow control with resource reservation • credit counter at sender NI tracks free space available in receiver NI buffers • credit packets can piggyback on response packets • end-to-end or link-to-link
Page 1 and 2: Special Course in Computer Science:
Page 3 and 4: Network-on-Chip (NoC) Why NoC OCP S
Page 5 and 6: From simpler to more complex chips
Page 7 and 8: Problems to solve • Cores that pe
Page 9 and 10: Some driving forces • Technical I
Page 11: NoC illustration
Page 14 and 15: OCP standard for on-chip communicat
Page 16 and 17: OCP Characteristics • IP Core •
Page 18 and 19: Flexibility of OCP • Several usef
Page 20 and 21: Some fundamental OCP concepts: Addr
Page 22 and 23: Some fundamental OCP concepts: In-b
Page 24 and 25: Some fundamental OCP concepts: Side
Page 26 and 27: Introduction • Network-on-chip (N
Page 28 and 29: Introduction • ISO/OSI network pr
Page 30 and 31: NoC Topology • Most direct networ
Page 32 and 33: NoC Topology • Folding torus topo
Page 34 and 35: NoC Topology • Indirect Topologie
Page 36 and 37: NoC Topology • (m, n, r) symmetri
Page 38 and 39: NoC Topology • Irregular or ad ho
Page 40 and 41: Switching strategies • Two main m
Page 42 and 43: Switching strategies • Allocating
Page 44 and 45: Switching strategies • VCT (virtu
Page 46 and 47: Routing algorithms • Static and d
Page 48 and 49: Routing algorithms • Minimal and
Page 50 and 51: Routing algorithms • Routing algo
Page 54 and 55: Clocking schemes • Fully synchron
Page 56 and 57: NoC Architectures examples
Page 58 and 59: HERMES • Developed at the Faculda
Page 60 and 61: Nostrum • Developed at KTH in Sto
Page 62 and 63: QNoC • Developed at Technion in I
Page 64 and 65: SPIN • Scalable programmable inte
Page 66 and 67: Emerging NoC paradigms Overall goal
Page 68 and 69: Novel Interconnect Paradigms for Mu
Page 70 and 71: Motivation • Increasingly harder
Page 72 and 73: Emerging Alternatives • Optical I
Page 74 and 75: Optical Interconnects • Board-to-
Page 76 and 77: Optical Interconnects • Waveguide
Page 78 and 79: Optical Interconnects • OIs have
Page 80 and 81: Optical Interconnects: Open Problem
Page 82 and 83: RF/Wireless Interconnects • Micro
Page 84 and 85: RF/Wireless Interconnects • Paths
Page 86 and 87: RF/Wireless Interconnects: Open Pro
Page 88 and 89: CNT Interconnects • Carbon nanotu
Page 90 and 91: Multi-Wall Carbon Nanotubes (MWCNT)
Page 94 and 95: Conceptual transmitter and receiver
Page 98 and 99: 3D and NoCs • 3D stacking technol

Lecture 9 - Åbo Akademi

Create successful ePaper yourself

Delete template?

Save as template?