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Linkgraph: Fix divide by 0 error when total linkgraph cost estimate <= 1.

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Jonathan G Rennison
2017-02-13 21:29:58 +00:00
parent e474f3b740
commit 7e89b9789f
1 changed files with 2 additions and 2 deletions
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4
src/linkgraph/linkgraphschedule.cpp
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@@ -33,7 +33,7 @@
* The cost estimate of a link graph job is C ~ N^2 log N, where * The cost estimate of a link graph job is C ~ N^2 log N, where
* N is the number of nodes in the job link graph. * N is the number of nodes in the job link graph.
* The cost estimate is summed for all running and scheduled jobs to form the total cost estimate T = sum C. * The cost estimate is summed for all running and scheduled jobs to form the total cost estimate T = sum C.
* The nominal cycle time (in recalc intervals) required to schedule all jobs is calculated as S = log_2 T. * The nominal cycle time (in recalc intervals) required to schedule all jobs is calculated as S = 1 + log_2 T.
* Hence the nominal duration of an individual job (in recalc intervals) is D = ceil(S * C / T) * Hence the nominal duration of an individual job (in recalc intervals) is D = ceil(S * C / T)
* The cost budget for an individual call to this method is given by T / S. * The cost budget for an individual call to this method is given by T / S.
* *
@@ -61,7 +61,7 @@ void LinkGraphSchedule::SpawnNext()
for (auto &it : this->running) { for (auto &it : this->running) {
total_cost += it->Graph().CalculateCostEstimate(); total_cost += it->Graph().CalculateCostEstimate();
} }
uint scaling = FindLastBit(total_cost); uint scaling = 1 + FindLastBit(total_cost);
uint cost_budget = total_cost / scaling; uint cost_budget = total_cost / scaling;
uint used_budget = 0; uint used_budget = 0;
std::vector<LinkGraphJobGroup::JobInfo> jobs_to_execute; std::vector<LinkGraphJobGroup::JobInfo> jobs_to_execute;