VSMP (virtual symmetric multiprocessing) is a method of SMP (symmetric multiprocessing) in which two or more virtual processors are mapped inside a single virtual machine or partition. This makes it possible to assign multiple virtual processors to a virtual machine on any host having at least two logical processors. VSMP can be employed in conjunction with multithreading, which is the ability of a program to concurrently manage multiple user requests.
In SMP, multiple programs are run by two or more processors that share a common OS (operating system) and memory. A single copy of the OS is in charge of all the processors. SMP systems are considered better than MPP (massively parallel processing) systems for online transactions in which many users are likely to access the same database at the same time.