The document discusses computer organization and architecture with a focus on processor-level parallelism and multiprocessors. It covers Flynn's taxonomy of computer architectures, including SISD, SIMD, MISD, and MIMD classifications, as well as the challenges and benefits of parallel processing in improving computational speed. Key concepts include memory organization for multiprocessor systems and cache coherence protocols.

1. Dr. S. Pradeep Narayanan, Assistant Professor,
Senior Grade I, SENSE, VIT Chennai.
ECE3004 –
Computer Organization and
Architecture

2. ➢ Processor level parallelism - Dependency,
➢ Flynn taxonomy,
➢ Memory organization for Multiprocessors
system,
➢ Symmetric Multiprocessor,
➢ Cache Coherence and The MESI Protocol.
Module 7 : Multiprocessors

3. – It is the technique which provides simultaneous data processing for the purpose
of increasing the computational speed of a computer system.
– parallel can be achieved by multiple functional unit that perform identical or
different operations simultaneously.
- In computers, parallel processing is the processing of program instructions by
dividing them among multiple processors with the objective of running a
program in less time.
- The simultaneous use of more than one CPU to execute a program. Ideally,
parallel processing makes a program run faster because there are more engines
(CPUs) running it.
In practice, it is often difficult to divide a program in such a way that separate
CPUs can execute different portions without interfering with each other.
Parallel Processing

4. ➢ Single Instruction, Single Data Stream - SISD
➢ Single Instruction, Multiple Data Stream - SIMD
➢ Multiple Instruction, Single Data Stream - MISD
➢ Multiple Instruction, Multiple Data Stream- MIMD
Multiple Processor
Organization
Flynn’s Taxonomy is a classification of a
computer architectures:

5. ✓ Single processor.
✓ Single instruction stream.
✓ Data stored in single memory.
✓ Uni-processor.
Single Instruction, Single
Data Stream - SISD

6. ▪ Single machine instruction.
▪ Controls simultaneous execution.
▪ Number of processing elements.
▪ Lockstep basis.
▪ Each processing element has associated data
memory.
▪ Each instruction executed on different set of
data by different processors.
▪ Vector and array processors.
Single Instruction, Multiple
Data Stream - SIMD

7. ✓ Sequence of data.
✓ Transmitted to set of processors.
✓ Each processor executes different instruction
sequence.
✓ Never been implemented.
Multiple Instruction, Single
Data Stream - MISD

8. Multiple Instruction,
Multiple Data Stream - MISD
✓ Set of processors.
✓ Simultaneously execute different instruction
sequences.
✓ Different sets of data.
✓ SMPs, clusters and NUMA systems.

9. Taxonomy of Parallel
Processor Architectures

10. Thank You