SMP Symmetric MultiProcessor

SMP stands for Symmetric MultiProcessor, which is a computer architecture design that allows multiple processors to share a single memory system. In an SMP system, all processors are considered equal and can perform the same set of functions. This is in contrast to asymmetric multiprocessing, where each processor may have a specific role or function.

In an SMP system, multiple processors are interconnected using a system bus or a high-speed interconnect such as a crossbar switch. Each processor typically has its own cache memory, and the processors share access to the main memory, input/output devices, and other system resources. This shared memory architecture enables processors to communicate and synchronize with each other efficiently.

Here are some key features and characteristics of SMP systems:

1. Symmetry: In an SMP system, all processors have equal access to the shared memory and resources. There is no master-slave relationship among the processors. They are considered symmetric and can perform similar tasks.
2. Shared Memory: The main memory is shared among all processors, which means that any processor can access any memory location directly. This simplifies programming and facilitates interprocessor communication by using shared variables.
3. Cache Coherency: Each processor has its own cache memory, which is used to store frequently accessed data. Cache coherence protocols ensure that if one processor modifies a memory location, the updated value is visible to all other processors. This ensures data consistency and avoids conflicts when multiple processors access the same memory location.
4. Load Balancing: SMP systems can distribute workload among multiple processors, allowing for efficient utilization of system resources. Tasks can be divided among processors to achieve better performance and responsiveness.
5. Scalability: SMP systems can be scaled up by adding more processors to the system. This can be done by adding additional sockets or by using multi-core processors, where multiple processing cores are integrated into a single physical chip.
6. Programming Model: SMP systems typically use a shared-memory programming model, where multiple threads or processes can be created to execute tasks concurrently. Programming languages like C, C++, and Java provide libraries and constructs to handle concurrent execution and synchronization in SMP systems.

SMP systems are commonly used in a wide range of computing systems, including desktop computers, servers, high-performance computing clusters, and multiprocessor systems-on-chip (MPSoCs). They provide increased performance, scalability, and responsiveness by harnessing the power of multiple processors working together in parallel.