välimuistivetoisia

Välimuistivetoisia, also known as cache-coherent non-uniform memory access (ccNUMA), is a computer architecture design that aims to improve the performance of multiprocessor systems by optimizing memory access. In a ccNUMA system, each processor has its own local memory, and all processors can access all memory, but accessing local memory is faster than accessing remote memory. This architecture is designed to reduce the latency associated with accessing remote memory by using a cache coherence protocol to ensure that all processors have a consistent view of the memory.

The cache coherence protocol in a ccNUMA system ensures that when a processor writes to a memory location, all other processors are notified and their caches are updated accordingly. This is achieved through a series of messages passed between processors, which can introduce some overhead. However, the benefit of reduced memory access latency often outweighs this overhead, especially in systems with a large number of processors.

Välimuistivetoisia systems are commonly used in high-performance computing, where the ability to quickly access large amounts of memory is crucial. They are also used in some database systems and other applications that require fast access to large datasets. The design of a ccNUMA system involves a careful balance between the benefits of reduced memory access latency and the overhead introduced by the cache coherence protocol. This balance is achieved through a combination of hardware and software optimizations, such as the use of non-uniform memory access (NUMA) aware memory allocators and the careful placement of data structures in memory.