Difference between Asymmetric and Symmetric Multiprocessing

In asymmetric multiprocessing, all the processors are not identical and they follow a master-slave relationship; whereas in symmetric multiprocessing, all the processors are identical and they share the main memory.

This tutorial explores both asymmetric and symmetric multiprocessing systems, highlighting their key differences in architecture, processor roles, and implementation approaches.

What is Asymmetric Multiprocessing?

Asymmetric Multiprocessing (AMP) is a multiprocessor architecture where two or more processors are controlled by one master processor. All CPUs are interconnected but are not self-scheduling, with specific tasks assigned to processors based on priority and importance.

In AMP systems, processors have different roles and capabilities. One CPU might handle operating system tasks while another performs input/output operations or specialized computations. This hierarchical structure allows for efficient task distribution but limits flexibility since each processor is dedicated to specific functions.

Asymmetric multiprocessing systems are commonly used in embedded systems and specialized applications where specific tasks need concurrent execution without requiring general-purpose computing flexibility.

What is Symmetric Multiprocessing?

Symmetric Multiprocessing (SMP) is a computer architecture where two or more identical processors connect to shared main memory and can execute any task assigned to them. All processors have equal access to system resources including memory, I/O devices, and operating system functions.

In SMP systems, the operating system treats all processors equally, allowing any processor to run operating system code or application programs. This provides better load balancing and fault tolerance, as tasks can be dynamically distributed among available processors.

Key Differences

Conclusion

The fundamental difference between asymmetric and symmetric multiprocessing lies in processor equality: AMP uses a hierarchical master-slave approach with specialized processors, while SMP employs identical processors with equal system access. Both architectures serve different computing needs based on performance requirements and system complexity.