Name: Saad Tanvir

ID: 14005065-083

Batch: 5

Program : BS Software Engineering

Resource Person: Mr. Khizar

Date: October 10, 2016

Computer Organization & Assembly Language

Assignment no 2

Contents1 Symmetric Multi Processing (SMP).........................................................................................3

1.1 Multiprocessing and Multiprocessor.................................................................................3

1.2 Definition:.........................................................................................................................3

1.3 Characteristics of SMP......................................................................................................3

2 Advantage of SMP vs. Single Processor..................................................................................4

3 Issues in Operating System of SMP.........................................................................................4

3.1 Simultaneous concurrent processes or threads..................................................................5

3.2 Scheduling.........................................................................................................................5

3.3 Synchronization................................................................................................................5

3.4 Memory management.......................................................................................................5

3.5 Reliability and fault tolerance...........................................................................................5

1 Symmetric Multi Processing (SMP)

1.1 Multiprocessing and Multiprocessor:

Multiprocessing is a term which means processing of programs by one or more processors at the same time.Microprocessor is a computer in which two or more processor share full access to a common RAM.

1.2 Definition:

SMP is called Symmetric Multi Processing. It is a technology in which programs are processed by multi processors and they share a common operating system and a memory. These processors communicate with each other through a shared memory. Symmetric means each processor can do anything which the other processor can do. All the processors can make changes to the any block of the memory and can also do Input / Output module communication. The processor’s view is also symmetrical as shown in Figure 1.

Figure 1: SMP Block Diagram

1.3 Characteristics of SMP:

Here are the characteristics of the Symmetric Multi Processors:

It has a two or more processors which has similar capacity. In SMP, all the processors share same memory and I/O module. In SMP, all the processors are connected by buses or internal connection. In SMP, all the processors have almost same memory access time. In SMP, all the processors have accessibility to I/O module through the same channels or through different

channels which has path to the same module. In SMP, all the processors are symmetrical. Each processor can perform all the tasks. In SMP, all the processors do not cause the programs to overload. In SMP, all the processors allow to run a mixture of programs. In SMP, all the processors have Uniform Access Memory (UMA).

2 Advantage of SMP vs. Single Processor

Following are the potential advantage of SMP over single Processor:

Parameters Symmetric Multi Processor Single Processor

Definitions If multiple processors performs all the task within the same operating system is called as Symmetric Multi Processor .

Of only one processor perform all the task of a system is known as single processor.

Specification In symmetric multiprocessors, eachProcessor are designed to handle all tasks.

In single processors, the processor are not designed to handle all tasks.

Reliability It is more reliable as failure in one Processor do not affect the other processors.

It is not reliable as failure in processor causesthe Entire system failure.

Performance Symmetric Multiprocessors have high performance due to parallel working of processors.

Single Processors have low performance rate as all work is to be processed by the single processor.

Design Implementation

It is difficult to implement a symmetricMulti processors as we have to achieve the synchronization of the multiple processors.

It is easy to implement as it consist of singleprocessor.

Enhance Speed The speed of the SMP can be achieved by the adding the processors.

The speed of the SMP cannot be achieved by the adding the processors.

Cost It is less costly because all the processors mayhave shared resources.

It is more costly because each separate single Processors require separate resources.

3 Issues in Operating System of SMP Following are the issues in Operating System of SMP:

3.1 Simultaneous concurrent processes or threads:

As multiple processors are working in parallel so we have to manage the kernel properly to avoid data corrupt or invalid operations.

3.2 Scheduling:

It is important part in operating system as it is responsible for the removal of the current running process from the CPU and selecting another process on the basis of specific strategy. So any processor may perform the scheduling. So, if multi processors are not designed to achieve the task scheduling then it may have the ability to task scheduling of the multiple threads from the same process simultaneously.

3.3 Synchronization:

Synchronization is important in multiprocessors programming as it prevent the use of shared resources at the same time to avoid the chance of inconsistent data. In multiprocessor, with active processes which have access to the same shared resources, we must have an efficient synchronization to avoid the mutual exclusion (prevent the simultaneously access to the shared resources) and ordering of the programs.

3.4 Memory management:

In operating system, Memory management is very essential to achieve the performance. In multi processor there should be coordination in blocks assigned to running program to achieve the high speed. In multiprocessors, the paging technique in different processors should be coordinated for consistency when a lot of processors share the same memory block.

3.5 Reliability and fault tolerance:

Operation System in SMP should be designed that then can automatically detect the problem and recognizes the failure of processor and rebuild the essential structure accordingly.