Xiao Liu PhD Thesis.pdf - Faculty of Information and Communication ...

skipped if self-recovery applies. As shown in Table 7.1, our temporal violation
handling point selection strategy is to apply the adaptive modification process for
probability threshold to the handling point selection rule.
The input parameters for the strategy include the necessary and sufficient
checkpoint, the probability time deficit, the probability time redundancy and the
probability threshold. Since handling point selection is based on the results of the
state-of-the-art checkpoint selection strategy, i.e. the minimum time redundancy
based checkpoint selection strategy where the time overhead is negligible, the
computation of the probability time redundancy according to Definition 7.2 can be
included in the checkpoint selection process [56]. Therefore, since PT is a variant,
the only extra cost for computing the input parameters is for the probability time
deficit according to Definition 7.1. After the input parameters are specified, the
current probability of self-recovery is obtained according to Definition 7.3 and
compared with the adaptively updated probability threshold to further decide
whether the current checkpoint needs to be selected as a temporal violation handling
point or not. The time overhead for our temporal violation handling point selection
strategy can be viewed negligible since it only requires several steps of simple
calculation. In the next section, we will evaluate the performance of our strategy
comprehensively.
7.3 Evaluation
In the existing work, temporal violation handling point selection is regarded the
same as checkpoint selection, hence the existing state-of-the-art checkpoint selection
strategy (with the minimum number of selected checkpoints)
CSS TD [22] is
implemented as the benchmark for comparison with ours. The detailed description
for
CSS TD and its performance better than the other 8 representative strategies are
omitted in this chapter which can be found in [22]. In addition, to evaluate the
effectiveness of our adaptive strategy, a pure random handling point selection
strategy denoted as RA is also implemented. RA selects handling points at every
necessary and sufficient checkpoint in a pure random fashion. The selection rule of
RA is as follows: at a necessary and sufficient checkpoint
a p
, a random value
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