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Joydeep Sen Sarma commented on MAPREDUCE-2027: ---------------------------------------------- Scott - do you want to take care of the other issue you found (different logic for starting reducer in JIP vs. FS) in this one as well? > fair share scheduler causes unnecessary preemption under some conditions > ------------------------------------------------------------------------ > > Key: MAPREDUCE-2027 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-2027 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: contrib/fair-share > Reporter: Joydeep Sen Sarma > > When the cluster hits speculative cap - JobInProgress does not speculate any > more. however FairShare Scheduler continues to believe that tasks need to be > speculated. > Under such conditions, FS Scheduler will start preempting repeatedly (because > from it's perspective - certain jobs are not getting the slots they deserve > (for speculative tasks)). > There may be other reasons for excessive preemption as well - this one stood > out clearly. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.