Parallel Computing - Overview Flashcards
What is decomposition?
The name give to the partitioning process
What are the two types of parallelism?
Data parallelism and task parallelism.
What is data parallelism?
The same code segment runs concurrently on each processor, but each processor is assigned its own part of the data to work on.
If one processor can perform the arithmetic in time t, then ideally how long can p processors perform the arithmetic?
Ideally, p processors can perform the arithmetic in time t/p.
What are four ways parallelism is exploited and enchanted within the operating system and hardware components of a parallel computer?
Operating system
Arithmetic
Memory
Disk
What is task parallelism
Each process performs different operations in parallel. “Coarse grain” parallelism because the computational work is spread into just a few suntans.
What is data parallelism?
The same code segment runs concurrently on each processor, but each processor is assigned its own part of the data to work on.
What are the three forms of arithmetic parallelism?
Multiple execution units: add, sub, mult, and div are each done in separate execution units. Allows several execution units to be used simultaneously, because they operate independently.
Fused multiply-add: overlap a floating-point multiply-add operation with a single rounding. Enables operation to complete in one computer rounding.
Superscalar arithmetic: ability to issue several arithmetic operations per cycle.
What memory features lend themselves to parallelism
Memory interleaving
Multiple memory ports
Multiple levels of the memory hierarchy
Cache memory
Types of disk parallelism
RAID and disk striping
