Computer Architecture multi processor seminar Mustansiriya University Department of Education Computer Science

1. MULTI PROCESSOR
BY
RAFIDH

2. Outline:
1. Flynn's taxonomy
2. Multi processor
Multiple cpu with shared memory
UMA
NUMA
3. Multi computer
Tightly Coupled Systems
Interconnection

3. Flynn's taxonomy: is a classification of
computer architectures, proposed by Michael
J. Flynn in 1966 The classification system has
stuck, and has been used as a tool in design of
modern processors and their functionalities.
Since the rise of multiprocessing central
processing units (CPUs), a
multiprogramming context has evolved as an
extension of the classification system.
1. Flynn's taxonomy

4. Flynn’s Taxonomy uses two basic
concepts: Parallelism in instruction
stream, and parallelism in data stream.
Any CPU system has (n) program
counter(pc), so there are (n)
“instruction stream” that can execute
in parallel.
A data stream can be used as a
sequence of data, and there exist 4
possible combinations.

5. 1.SISD(Single Instruction Single
Data)
A processor that can only do one job at a time from start to
finish.

6. 2. SIMD(Single Instruction
Multiple Data)
controls the simultaneous execution of
a number of processing elements, so
that each instruction is executed on a
different set of data by the different
processors.

7. 2. SIMD(Single Instruction
Multiple Data)

8. 3. MISD(Multiple instructions
single data)
A sequence of data is transmitted to a set of processors,
each of which executes a different instruction sequence
This structure is not commercially implemented.

9. 4. MIMD(Multiple instruction
Multiple Data)
 is a technique employed to achieve parallelism.
Machines using MIMD have a number of
processors that function asynchronously and
independently. At any time, different
processors may be executing different
instructions on different pieces of data.

10. 4. MIMD(Multiple instruction Multiple Data)

11. 2-Multiprocessor System:
Definition
A computer system in which two or more
CPUs share full access to a common RAM
.

12. Shared memory parallel computers vary widely, but
generally have in common the ability for all processors to
access all memory as global address space.
Multiple processors can operate independently but
share the same memory resources.
Changes in a memory location effected by one
processor are visible to all other processors.
Historically, shared memory machines have been
classified as UMA and NUMA, based on memory access
times.
Shared Memory

13. . . .
interconnection network
. . .
processor
1
cache
processor
2
cache
processor
N
cache
memory
1
memory
M
memory
2

14. 1. Uniform Memory Access (UMA)
Uniform memory access (UMA) is a shared memory
architecture used in parallel computers. All the
processors in the UMA model share the physical
memory uniformly. The UMA model is suitable for
general purpose and time sharing applications by
multiple users.

16. 2. Non-Uniform Memory Access (NUMA)
Non-uniform memory access (NUMA) is a
computer memory design used in
multiprocessing, where the memory access time
depends on the memory location relative to the
processor. Under NUMA, a processor can access
its own local memory faster than non-local
memory (memory local to another processor or
memory shared between processors).

18. Definition:
Architecture in which each processor
has its own memory rather than
multiple processors with shared
memory. PC multi-core, although it
looks similar, it will not have multiple
computers because multiple cores
share a common memory
3.Multi computer:

19. 3. Multi computer
Definition:
• Are tightly-coupled CPUs that do not
share memory (each one has its
Memory)
• These systems are also known by a
variety of other names, cluster
computers and COWS (Cluster of
Workstations).

20. Tightly Coupled Systems
Tightly coupled multiprocessor systems contain
multiple CPUs that are connected at the bus level.
These CPUs may have access to a central shared
memory ( UMA), or may participate in a memory
hierarchy with both local and shared memory
(SM)(NUMA). Both ranges of processors had their
own onboard cache but provided access to shared
memory; the Xeon processors via a common pipe
and the Opteron processors via independent
pathways to the system RAM

21. MULTICOMPUTER HARDWARE
Interconnection Topologies:
 An interconnection network in a parallel machine transfers
information from any source node to any desired destination
node .
 The network is composed of links and switches, which helps to
send the information from the source node to the destination
node
Single Switch
RING GRID
Double Torus CUBE
4D Hypercube

22. Ring
 This is one of the simplest ways of connecting nodes
with each other. The nodes are connected with each
other to form a ring. For a node to communicate with
some other node, it has to send the messages to its
neighbor. Therefore, the data message passes through
a series of other nodes before reaching the destination.
This involves increased latency in the system.

23. Mesh network
 In a mesh network, multiple nodes are connected with
each other. Each node in the network is connected to
every other node in the network. This arrangement
allows proper communication of the data between the
nodes. But, there are a lot of communication
overheads due to the increased number of node
connections.

24. Hypercube
 This topology consists of connections of the nodes to
form cubes. The nodes are also connected to the nodes
on the other cubes.

25. Multicomputer Multiprocessor
 1.A multiprocessor system is
simply a computer that has more
than one CPU on its
motherboard.
 2. Multiprocessing is the use of
two or more central processing
units (CPUs) within a single
computer system.

 3. Multiprocessors have a single
physical address space
(memory) shared by all the
CPUs

 4. A multiprocessor would run
slower, because it would be in
ONE computer.
 5. A multi-processor is a single
system with multiple CPU'
1.A computer made up of several
computers. similar to parallel computing.
2. Distributed computing deals with
hardware and software systems containing
more than one processing element,
multiple programs, running under a
loosely or tightly controlled regime.
3. multicomputer have one physical
address space per CPU.
4. It can run faster
5. A multi-computer is multiple
computers, each of which can have
multiple processors. Used for true parallel
processing

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