[jira] [Created] (MESOS-10128) Performance regression in HierarchicalAllocations_BENCHMARK_Test.PersistentVolumes

["Andrei Sekretenko (Jira)" <ji...@apache.org>]

Andrei Sekretenko created MESOS-10128:
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             Summary: Performance regression in HierarchicalAllocations_BENCHMARK_Test.PersistentVolumes 
                 Key: MESOS-10128
                 URL: https://issues.apache.org/jira/browse/MESOS-10128
             Project: Mesos
          Issue Type: Bug
            Reporter: Andrei Sekretenko
            Assignee: Andrei Sekretenko


Compared to 1.9.0, HierarchicalAllocations_BENCHMARK_Test.PersistentVolumes ran on 1.10.x branch/current master shows a regression (up to 50 times in some cases) and exhibits a quadratic dependence of allocation time versus the number of agents in the few-framework cases.

This regression was introduced by 
https://reviews.apache.org/r/71460 
which employed a single `Resources` object to track offered/allocated resources of all agents on the cluster
and exacerbated by https://reviews.apache.org/r/71488 that followed a similar approach.

In the case when resources of agents are non-addable (for example, each agent has an unique persistent volume), this results in O(N^2) asymptotic time complexity versus the number of agents due to the addition/subtraction of Resources being O(X*Y) where X and Y are number of individual `Resource`s on the left and on the right side.

Moreover, the approach taken in those PRs violates the convention that `Resources` belonging to different agents should not be added/subtracted.



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