SusumuDate,YukiMatsui,YasuhiroWatashiba,TakashiYoshikawa,ShinjiShimojo

CybermediaCenter,OsakaUniversity

JobSchedulerSimulatorExtensionforEvaluatingQueueMappingtoComputingNode

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[Background]Fromsupercomputingcenter viewpoint

• HighPerformanceComputingEnvironmenthasbeenplayingaroleofgreaterimportance.

• Efficientandhigherjobthroughputisanimportantmissioninsupercomputingcenters.Waitingtimeisalsoimportant..

SupercomputingcenterUser

Job

Computingresults

ComputingClusterisamajorarchitectureinHPC

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[Background]Fromasystemadministrationandmanagementviewpoint

administrators ForHigh-throughputadministration,・Utilizationrestrictionofcomputationalresourcesonschedulerqueue・Per-userconfigurationintermsofjobpriority・Selectionofschedulingalgorithm

Duetothescale-outandarchitecturalheterogeneityofsystems,alotofconfigurationparametersshouldbeconsidered.

Administrators’workloadisbecomingheavier.

Amechanismthatreducesadministrators’workloadisdemanded.

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[Configurationexample]Queuemappingconfiguration

• Jobschedulerhasmultiplequeuesconfiguredinmostcases.• Asinglequeuemightbegoodtheoretically?butmultiplequeueare

configuredinreality.• Hybridsystemofdifferentarchitecture• Prioritizationofjobs• etc

Mappingbetweenqueuesandcomputingnodesbecomesahardconfigurationproblem.

AvailablefromQueue1

AvailablefromQueue2

Queue1Mapping:A~F

Queue2Mapping:D~H

ABCD

EFGH

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Examplecase(1/2)

Initialstate:jobrequesting4nodesonqueue2cannotbeassigned.

Queue1Mapping:A~F

Queue2Mapping:D~H

ABCDEFGH

Requesting4nodes.

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Examplecase(2/2)

ABCDEFGH

ABCDEFGH

IfCismappedtoQueue2,thewaitingjobrequesting4nodescanbeexecutedonC,F,GandH.

IfE,FarenotlinkedtoQueue1,therunningjobonDandEcouldbeexecutedandthewaitingjobrequestinng 4nodescanberunonE,F,GandH.

AddC

E,Fnotlinked

Actualexample:queuemappingonOCTOPUS

CPUnodeCPUnodeCPUnode

GPUnode

GPUnodeGPUnodeGPUnode

CPUqueue

GPUqueue

ApartofGPUnodescanbeusedforCPUnodes.

HowmanyGPUnodescanbeusedagainstourworkload?

OsakauniversityCybermedia cenTer Over-Petascale UniversalSupercomputer)

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[Motivation]Difficultiesinconfiguringqueuemapping

administratorNoobjectivecriteriaforconfiguration,relyingonknowhowandexperience

Propermappingconfigurationhavetobeassisted.

Alotof combinationbetweenconfigurationparameters havetobeconsideredinatrial-and-errormanner.

He/shecannotsaywhetherhis/herconfigurationgainhigh-throughputornot.

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[Approach]UseofJobschedulersimulationforanalyzingthebehaviorofjobassignmentsinsystem

• Anumberofjobschedulersimulatorsareavailable.GridSim,Slurm simulator,gem5-gpusimulator,MERPSYS,ALEA…

• However,mostofjobschedulersimulatorsdonothelpusinexploringtheanalysisspaceofqueuemappingproblem.• Manyofjobschedulersimulatorsfocusonschedulingalgorithm

researchdevelopment.Onlysinglequeueissupported.

• Manyofthemdoesnotallowustoconfigurethemappingrelationshipbetweencomputingnodeandqueue.

Bymodifyingandextendinganexistentschedulersimulator,werealizeatoolthatfacilitatesthesystemadministratortolearnwhichqueuemappingisbetterforacertainseriesofjobrequests.

Ourapproach: todevelopsuchatoolbasedonALEA[Klusáček et.al.2010].

ALEA:agrid-simbasedsimulatorHowever,threefunctionalitiesatleastarelackedforachievingthegoal.

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ALEAarchitecture andlackedfunctionalities.

Jobscheduler

queue Jobselection

2.Submissionjudgement

Request:3node Cluster

3.AssignComputingnode

job

Assignedto

1.Mappingcannotbeconfigured.

2.ALEAdoesnotallowsimulationtochangethestatusofcomputingnodes,meaningthatALEAjustcountsthenumberofbusy/freenodes.

3.ALEAdoesnotdistinguish(identify)computingnode,meaningthatitdoesnotallowsimulationtochooseanyspecificcomputingnode,althoughinternaldatastructureidentifieseachnode.

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Solution:ComputingnodemanagementmoduleasExtensiontoALEA

ComputingnodemanagementmoduleComp.nodestatusmanagementfunc.

Thisfunc.EnablesFine-grainedmapping

configuration

Mappingmng/adm func.

Thisfunc.allowssimulationtoassignaspecificcomputingnodebyidentifyingand

understandingaspecificnodestatus.

Assignmentdeterminationfunc.

Thisfunc.enablessimulationtodeterminecomputingnodeforassignmentdestinationnode.

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Evaluation

1.Comparisonwithrealenvironment

＝

2.Timetosearchallanalysisspace

Toverifywhethertosimulatethebehaviorofjobsonactualclustersystem

Toknowhowlongittakestoderivetopropermappingconfiguration

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Experimentconditions

･･･

50jobs

4並列⽤優先度⾼

1並列⽤

･･･16nodes

投⼊ FIFO 割当

Clustersystem

Jobscheduler

For4-nodeparallelPriorityHigh

Forsingle-node

Submit Assign

1node/4node・queuefor4nodehashigherpriority

・jobisselectedinFCFS

・nodededication・nodifferenceinnodeperformance・usenon-overlappednodewithpriority

・FCFS(First-come,First-Served)・Arrival: in60secondsafterthepreviousjob・Executiontime:1~120seconds・#ofnodes:1or4nodes.

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Experiment1: Comparison

Simulator Realenvironment

Simulatorbehavesinalmostthesamewayastherealenvironmentintermsofthroughput

• ClustersystemwithSlurm deployedissimulated.

throughput

#ofcomputingnodesmappedtoasingle-nodequeue

#ofcomputingnodesmappedtoa4-nodequeue

#ofcomputingnodesmappedtoa4-nodequeue

#ofcomputingnodesmappedtoasingle-nodequeue

throughput

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Experiment2:Executiontimetosearchtheanalysisspace

Executiontimedramaticallyincreases..

#ofcomputingnodes

Executiontim

etose

archth

eanalysisspace

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Experiment2:Executiontimetosimulateamappingpattern

Executiontimeisnotdependenton#ofcomp.nodes.

1

#ofcomputingnodes

Executionim

etosimulateamappingpattern

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Summary

Problem：Currently,administratorsarerelyingontheirownexperienceandknowhowonscheduler’squeuemapping.

Goal:Buildajobschedulingsimulatorthatallowsadministratorstoinvestigatethebehaviorofjobsonqueue-computingnodemappings.

Evaluation：Sofar,wehavecheckedthatextendedsimulatorofferssimulationresultsclosetorealenvironment.

FutureIssues• Reducingtheexecutiontimetosearchanalysisspace.