This document contains the summary of a session on multiprocessor systems. It discusses various topics related to multiprocessors including classification of multiprocessors into tightly coupled and loosely coupled systems based on memory organization. It describes different interconnection structures for multiprocessors like shared bus, multiport memory, crossbar switch, multistage switching network and hypercube. It also discusses arbitration techniques for resolving bus conflicts and topics related to interprocessor communication and synchronization that will be covered in the next session.

1. CS304PC:Computer Organization
and Architecture (R18 II(I sem))
Department of computer science and engineering (AI/ML)
Session 31
by
Asst.Prof.M.Gokilavani
VITS
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2. TEXTBOOK:
• 1. Computer System Architecture – M. Moris Mano,
Third Edition, Pearson/PHI.
REFERENCES:
• Computer Organization – Car Hamacher, Zvonks
Vranesic, Safea Zaky, Vth Edition, McGraw Hill.
• Computer Organization and Architecture – William
Stallings Sixth Edition, Pearson/PHI.
• Structured Computer Organization – Andrew S.
Tanenbaum, 4th Edition, PHI/Pearson.
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3. Unit V
Reduced Instruction set computer: CISC
characteristics, RISC characteristics.
Pipeline and vector processing: parallel processing,
pipelining, Arithmetic pipeline, instruction pipeline,
RISC pipeline, vector processing, array processing.
Multi Processors: Characteristics of multiprocessors,
interconnection structures, Interprocessors arbitration,
Interprocessors communication and synchronization,
cache coherence.
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4. Topics covered in session 30
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•Reduced Instruction set computer
•Pipeline and vector processing
•Multi Processors

5. Introduction
• Multiprocessor system is an interconnection of
two or more CPUs with memory and input-output
equipment
• The components that forms multiprocessor are
CPUs IOPs connected to input –output devices ,
and memory unit that may be partitioned into a
number of separate modules.
• Multiprocessor are classified as
• multiple instruction stream
• multiple data stream (MIMD) system.
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6. Why Choose a Multiprocessor?
• A single CPU can only go so fast, use more
than one CPU to improve performance
• Multiple users
• Multiple applications
• Multi-tasking within an application
• Responsiveness and/or throughput
• Share hardware between CPUs
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7. What you the difference between
Multiprocessor and Multicomputer?
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8. How multiprocessor are classified?
• Multiprocessor are classified by the way their
memory is organized, mainly it is classified into two
types
• Tightly coupled multiprocessor
• Loosely coupled multiprocessor
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9. Tightly coupled Multiprocessor
• A multiprocessor is a tightly coupled computer system
having two or more processing units (Multiple
Processors) each sharing main memory and
peripherals, in order to simultaneously process
programs.
• Tightly coupled Multiprocessor is also know as shared
memory system.
Loosely-coupled multiprocessor
• Loosely-coupled multiprocessor systems (often referred
to as clusters ) are based on multiple standalone single
or dual processor commodity computers interconnected
via a high speed communication system.
• Loosely-coupled multiprocessor is also known as
distributed memory.
• Example: A Linux beowulf cluster
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10. Difference b/w Tightly coupled and
Loosely coupled multiprocessor
Tightly coupled
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11. Interconnection Structures
• The physical forms for establishing an
interconnection network .
• Time shared common bus.
• Multiport memory.
• Crossbar switch
• Multistage switching network.
• Hypercube system.
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12. Time –shared common bus
• A system common bus multiprocessor system
consists of a number of processors connected through
path to a memory unit.
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14. Multiport Memory
• A multiport memory system employs separate buses
between each memory module and each CPU.
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15. Cross bar switch
• The crossbar switch organization consists of a
number of cross points that are placed at
intersections between processor buses and
memory modules parts.
• The small Square in each cross point is a
switch that determines the path from a
processor to a memory module.
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16. Cross bar switch
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18. Multistage switching Network
• The basic component of a multistage network is a
two- input , two- output interchange switch.
• There are control sign associated with switch that
establish the interconnection between the input and
output terminals.
• The switch has the capability connecting input A to
either of the outputs.
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19. Multistage switching Network
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21. Hypercube Interconnection
• The hypercube or binary n-cube multiprocessor
structure is loosely coupled system composed of
N=2n processor interconnected in an n-
dimensional binary cube.
• Hyper cube structures for n = 1,2,3.
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22. Hypercube Interconnection
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23. Interprocessors arbitration
• Arbitration logic resolves bus conflict
• It would be the part of system bus controller
• Arbitration procedures services all processor
requests on the basis of established priorities.
• Two types
– Serial Arbitration procedure
– Parallel Arbitration procedure
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24. Serial Arbitration procedure
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25. Parallel Arbitration procedure
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26. Dynamic Arbitration Algorithm
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27. Topics to be covered in next session 32
• Interprocessors communication and
synchronization
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Thank you!!!