The Sevcik 1994 Model
This is a model of application speedup, which is useful for modeling
jobs that are scheduled on varying partition sizes (that is, moldable
or malleable jobs).
It has been shown that actual speedup functions can indeed be
represented in this form.
Speedup Function
The speedup function is modeled using two inputs and three parameters.
The inputs are
| W | the total work done by the job |
| n | the number of processors allocated |
The parameters are
| phi | the load imbalance of threads |
| alpha | the amount of sequential and per-processor work |
| beta | communication and congestion delays |
The formula for the runtime of the job is then
Suggested values for these parameters are
| | W | phi | alpha | beta |
| workload1 | 1000 | 1.02 | 0.05 | 0 |
| workload2 | 1000 | 1.3 | 25 | 25 |
Where the values for W are mean values, and the distribution is
selected so as to achieve the desired variance.
In the first workload, all jobs have nearly ideal speedup.
In the second, small jobs experience poor speedup while large jobs
experience reasonable speedup.
Parallel Workloads Archive - Models