Peak performance - observe sustained performance = SLOW
#Starvation
Absence of work: not enough parallelism by user application to keep all the system resources busy, or there is enough work but it is not distributed evenly (load-balanced).
#Latency
The time it takes for information to travel from one part of a system to another.
- local memory access
- execution pipeline
- network requests
- etc.
#Overhead
The amount of additional work beyond the required amount to perform the computation
- task scheduling
- synchronization of parallelism
- support communication
- etc.
#Waiting
Waiting for shared resources due to contention of access degrades performance. Two or more requests at the same time to the same resource.
Peak Performance