Hello, We have an issue on our cluster with the implementation of Preemption using Maui. I have configured two queues and corresponding QOS levels in maui.cfg, one preemptor, one premptee (we are running Maui version 3.3):
PREEMPTPOLICY SUSPEND QOSWEIGHT 10 QOSCFG[hi] PRIORITY=10000 QFLAGS=PREEMPTOR QOSCFG[lo] PRIORITY=10 QFLAGS=PREEMPTEE CLASSWEIGHT 10 CLASSCFG[debug] QDEF=hi QLIST=debug CLASSCFG[low-priority] QDEF=lo When we have a premptee job runnning and submit a preemptor job, the preemptee job gets suspended just as it should, while the preemptor job runs. If there is no other job in the queue, the suspended job resumes execution afterwards and finishes properly. The problem occurs if the preemptor needs less processors than the preemptee, and there is another job in the queue that fits in the resulting gap. For example, I submit a preemptee job on the two test nodes we use. Then I submit a preemptor job that only needs one node. Now, while the preemptor is running, one node is idle. If at this point there are (other preemptee) jobs in the queue or submitted that only need one node, than all these jobs will be executed before the suspended job resumes, despite the suspended job waiting. This happens even though they have lower priority (checked through diagnose -p) tghan the suspended job and don't even fit into the backfill window created by the preemptor job (i.e. have a greater wall time requirement). I have searched the archives of this list and read any related thread I could find, and consequently tried ALL the following settings in various combinatons (and restarted Maui after each change): BACKFILLPOLICY: NONE, FIRSTFIT, BESTFIT RESERVATIONPOLICY: CURRENTHIGHEST, HIGHEST, NEVER RESERVATIONDEPTH: 0, 1, 3 I do absolutely not understand how Maui can overlook the suspended job and execute a lower priority job in the same QOS from the queue, even if backfilling and reservations are disabled. I'd appreciate any suggestions why this happens and how to mend it. Robert -- Robert Jacobi Research Assistant University of Arizona Department of Aerospace& Mechanical Engineering 1130 N. Mountain Ave. Tucson, AZ, 85721-0119 tel: +1 (520) 621 4369 mail: [email protected] The less time you spent on algebra in life, the more time you have to be a happy person. (Kerschen) Doubt is not a pleasant condition, but certainty is absurd. (Voltaire) All great truths begin as blasphemies. (Shaw) Denken ist etwas, das auf Schwierigkeiten folgt und dem das Handeln vorausgeht.(Brecht) _______________________________________________ mauiusers mailing list [email protected] http://www.supercluster.org/mailman/listinfo/mauiusers
