IntelKnightsLanding:performanceandusabilityassessmentforscientific

communitiesE.Boyer,G.Hautreux (GENCI)- Technologicalwatchgroup,

GENCI-CEA-CNRS-INRIAandFrenchUniversities

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• InchargeofnationalHPCstrategy forcivilresearch• Morethan 6,5Pflops available on3nationalcenters (CINES,IDRISandTGCC)

• Partnerships attheregional level• Equip@meso,15partners

• Represent FranceinthePRACE research infrastructure

• Promote theuseofsupercomputing forthebenefit ofFrenchscientificcommunities andforindustries• Specific actiontoSMEs through theSimseo intiative

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Frioul:KNLbased prototype

• AtosSequana cell @CINES,Montpellier(France)• 3 partitionsof48KNL7250nodes,146Tflops peak

• 16Quadrantcluster+Cachememorynodes• 16Quadrantcluster+Flatmemorynodes• 16Quadrantcluster+Hybrid memorynodes

• Quadrantmodeused forboth partitions• Poorresults inother processormodes

• BIOSversionsshould be updatedWork inprogress with Atos

• Highlevel support• Thanks toAtosandIntelteams

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• Thecomparisonismadebetween• Frioul (XeonPhi,KnightsLanding,EDRinterconnect)• Occigen (Broadwell node:2x14cores@2.60GHz,FDRinterconnect)

▪ Theoverall performanceforthose applicationsatthemoment▪ Node tonode comparison

▪ Energy efficiency isanestimationusingTDPratio

à Results for14applications

à Assesment ofmemorymodes,vectorization impact,…

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“Real”applicationsresults

KNLmemorymodes▪ ImpactofMCDRAM

▪ Applicationsranin« fullflat »and« cache »mode▪ Resultsprovidedareforthebesttestcase(favorabletoflatmode)▪ NorealimpactofusingMCDRAMforourapplications

▪ Testcases donotfitinMCDRAM,realapplicationsareusingmemory▪ Lotsofindirections leadingtobelatencybound▪ Currentlytestingthehybridmode, itcouldbethesolution

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Firstconclusions▪ Easeofuse

▪ Notroublewithportability▪ Goodspeed-upinafewdayswork▪ Energyefficiency▪ Stilltroubleswithscalability

▪ PerformanceofIBdrivers?IBparameters?BIOSfixes?

▪ Achoiceconcerningthememorycanbemade▪ Cacheforlargeinfrastructureswithawidevarietyofusers▪ AcomparisonFlatvsCacheshouldbedoneifyouonlyhaveafewusers

▪ FullopeningoftheplatforminApril▪ Frenchcommunityatfirst▪ Helpustohaveabetterfeedbackontheplatform▪ moreapplicationsandnewfocusonDLapplications

▪ AKnightMillplatformmaybeconsideredIXPUGBoFISC17 6

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0,5

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1 2 4 8 16 32 64

Spee

d up

Working time (hours)

Effective mean speed up obtained after 2 workshops (Haswell vs KNL)

Performance vs Haswell 24c

Energy efficiency vs Haswell 24c

Thank you foryour attention

Questions?

eric.boyer@genci.fr

gabriel.hautreux@genci.fr

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