The Leland & Ott 1986 Model
This is actually a model of process runtimes in an interactive
environment, rather than a model of a parallel workload.
Its distinction lies in the innovative functional form used to
describe the distribution.
Process runtimes
The proposed distribution is valid for processes that are longer than
3 seconds.
With this restriction, the probability that a process will run for
more than t seconds is proportional to tk,
with k in the range -1.25 < k < -1.05.
A subsequent study by Harchol-Balter and Downey reaffirmed this model,
and provided the following formulae:
- k in the range -1.3 < k < -.8, with k = -1
a reasonable default.
- Prob(runtime > t sec | runtime > 1 sec) = tk
For k = -1, this is 1 / t.
- Prob(runtime = t sec | age = 1 sec) = -k tk-1
For k = -1, this is 1 / t2.
This model is described in the following papers:
[leland86] and
[harcholb97].
Parallel Workloads Archive - Models