Symmetric Multiprocessing (SMP) REVIEW

Categories of Computer Systems Single Instruction Single Data (SISD) single processor executes a single instruction stream to operate on data stored in a single memory Single Instruction Multiple Data (SIMD) one instruction is executed on a different set of data by the different processors

Categories of Computer Systems Multiple Instruction Single Data (MISD) a sequence of data is transmitted to a set of processors, each of which executes a different instruction sequence. Never implemented Multiple Instruction Multiple Data (MIMD) a set of processors simultaneously execute different instruction sequences on different data sets

Parallel Processor Architecture MIMD Distributed memory (self-contained computers) Shared memory multiprocessor Clusters Symmetric multiprocessors (SMP) Master/Slave

Symmetric Multiprocessing Kernel can execute on any processor Typically each processor does self-scheduling from the pool of available process or threads portions of the kernel can execute in parallel in different processors

Symmetric Multiprocessor Organization . . . Processor Cache Cache Cache Main Memory I/O Subsystem

Multiprocessor OS requirements Must provide functionality of a multiprogramming OS plus additional features to support multiple processors Simultaneous concurrent processes or threads: kernel routines need to be reentrant Scheduling done by any processor, can create conflicts. Synchronization through locks is required. Memory management needs to be coordinated in the different processors Much more complex than just multiprogramming OS.