Explain Classification Based On Grain Size

This categorization is based on distinguishing the parallelism in a program to be executed on a multiprocessor system. The concept is to recognize the subtasks or instructions in a program which can be executed in parallel. E.g. there are three statements in a program and statements S1 and S2 can be exchanged. It implies, these are not serial as shown in Figure. Then S1 and S2 are able to be executed in parallel.

Figure: Parallel execution for S1 and S2

However it's not enough to check for parallelism between processes or statements in a program. The decision of parallelism too depends on the subsequent factors:

• Types and Number of processors available, it implies that architectural features of host computer
• Dependency of data, control and resources
• Memory organisation