Structure of Multiprocessor (UMA,NUMA,Distributed memory sysetm)
Multiprocessor systems can be categorized into different types based on their memory architecture and how they handle memory access among multiple processors. The three main types of multiprocessor systems are:
1. **Uniform Memory Access (UMA)**:
In UMA systems, all processors have equal access times to the shared main memory.
Memory is physically centralized and accessible with roughly the same latency for all processors.
UMA systems are typically easier to program since there's no significant difference in memory access times.
Examples include symmetric multiprocessing (SMP) systems, where each processor has equal access to the same memory pool.
2. **Non-Uniform Memory Access (NUMA)**:
NUMA systems have a memory architecture where access times to different parts of memory can vary.
In NUMA, memory is distributed across different nodes, and each processor may have faster access to its local memory but slower access to memory located on other nodes.
NUMA architectures are often used in large-scale multiprocessor systems and can provide high scalability.
Examples include many modern server architectures and high-performance computing clusters.
3. **Distributed Memory System**:
In a distributed memory system, each processor has its own separate memory space, and there is no shared global memory.
Processors communicate and share data explicitly through message-passing mechanisms, such as MPI (Message Passing Interface).
Distributed memory systems are common in massively parallel computing environments like supercomputers and some types of cluster computing setups.
Examples include many supercomputers like those based on the Cray architecture.
Each of these multiprocessor system types has its advantages and disadvantages, and the choice of architecture depends on factors like scalability, performance requirements, and the nature of the workload being executed.