1. Symmetric Multiprocessing (SMP)
REVIEW

2. 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

3. 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

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

5. 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

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

7. 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.