slowhyper-v

HyperV_MonAFreeToolFromTMurgentTechnologiesVersion1.
6IntroductionHyperV_MonisaGUItoolforviewingCPUperformanceofasystemrunningHyper-VfromMicrosoft.
VirtualizationaddsalayerofcomplexitytounderstandingtrueCPUusageofavirtualmachine.
Thistoolprovidesasimpletoviewsetofgraphstodepictactualprocessorutilization,including"overhead"processingduetotheuseoftheHypervisor.
HyperV_Monisnotintendedtobearegularmonitoringtoolthatyouuseeveryday.
Thistoolisdesignedtohelpyouunderstandwhatisgoingonwhenyouneedtoknowit.
Thetoolrequiresthatyouhave.
theNET3.
5FrameworkinstalledonthemachinethatyouwishtoruntheGUIon.
Ifyoudidn'tinstallServerCore,youcanplaceitontherootpartitionmachine,buttypicallyyouwanttoplacethisonadesktopthatisnotontheHyper-Vservertominimizeimpactontheserveritself.
ThetoolleveragestheRootPartitionWMIprovider–thesameinterfaceasisusedbySCVMMandthirdpartytools.
SoaslongastheremoteGUIuserhasWMIaccesstotheRootPartitionServeryouaregoodtogo.
SomeofthenewfeaturesinHyperV_MonalsoneedWMIaccesstotheVMsthemselves,butwillreasonablyoperateifaccesstotheVMsarenotavailable.
Thetoolhasnoinstaller.
Justanexewithaconfigurebutton.
Theterm"Overhead"isusedinthisdocumentandintheproductasashorthandtocapturetheconceptofprocessingthatisbeingperformedbytheHypervisoritself.
Technically,thisisnot"overhead"inthesenseofprocessingthatwouldnotbeoccurringifyoudidn'tvirtualize.
Whilesomeofthisprocessingtrulyrepresentsoverhead,someofitrepresentsprocessingthatwouldhaveoccurredindriversofthenon-virtualizedsystem.
SettingUpTheToolAftercopyingtheexeontoasystem,startitandmouseclickthe"Configure"button.
TheConfiguredialogisshowninFigure1.
Youmustenteraqualifiednameforthehostintherootpartitionoftheservertobemonitored.
Anyresolvablenamemaybeused.
TheDebugleveldefaultsto0–meaningnodebugging.
Youcanmovetheslidertotherighttoenabledebuggingandconfigurehowmuchinformationtolog.
Level1providesforerrorsonly.
Thelogfilewillbeappendedtointhecurrentworkingfolder.
Thepollingintervaldefaultsto1second.
Movetheslidertotherighttoslowdownpoling.
ThethreeConfigurationitemsarewrittentotheHKEY_CURRENT_USERhive.
Figure1-ConfigureScreenHyperV_MonrequiresaccesstotheWMIprovidersoftherootpartitionofthetargetmachine.
Thiscanprovetobeaproblemunlessthemachine(anduseraccountyouarerunningunder)thattheGUIisonisinthesamedomainastheRootPartition.
SeetheblogofMicrosoft'sJohnHowardhttp://blogs.
technet.
com/jhoward/default.
aspx(especiallyHyper-VRemoteManagementParts1-5)ifyouarehavingdifficulty.
Basically,ifyoucanrunwbemtestonyourclientmachineandconnecttotherootpartitionmachineyouwillbegoodtogo.
UsingTheToolFigure2showsanexampleoftheGUIinaction.
Atthebottomlayerofthedisplayisthehardware.
Notmuchtotalkaboutthere.
Itdoesn'tmatterwhatyourhardwarelookslike,thegraphicwilllooklikea1Urackserverfrommylab.
Someinformationisdisplayedidentifyingthehardware.
ThenextlayerupistheHypervisor.
OnlyMicrosoftHyper-V,andHyper-VR2aresupported.
Thenumberof"LogicalCPU"physicallyinstalledisdetectedanddepicted.
ActualCPUusageatthephysicallayerisreported.
Inourcase,thiswasasinglequad-coreprocessor.
Intheexample,almostalloftheCPUisrelatedtoGuestusageandisshowninalightershadeofgreen.
CPUusagetiedtoHypervisorFigure2-ASampleoftheGUIinAction!
callsisshownattheloweredgeinadarkergreencolor.
ItiseasiesttothinkoftheHypervisorcallsas"hypervisoroverhead",althoughtechnicallysomeofthat"overhead"isprocessingthatwouldhavebeenperformedtheguestwasonrawmetalhardware.
Thelast60intervalmeasurementsaredisplayed(1secondeach,bydefault)withthemostrecentintervaldisplayedontherightofthegraph.
Thebluespline(curvyline)representsarunninglongertermaverage(eachdotdepictsthemostrecent60-intervalaveragetotalCPUatthetimeoftheinterval)fortrending.
AbovetheHypervisorlayerthedisplayhastwomajorparts,situatedleftandright.
OntheleftistheRootPartitionOS.
ThisistypicallywhereyourServerCoreisrunning.
Intheexamplethiswasafullblown2008withAD,DNS,IIS,TerminalServices,andahostofotherthingstobeinteresting.
TheRootPartitionhas"VirtualProcessors",andHyper-Vwillsupplyoneforoneforeach"LogicalProcessor"intheHypervisor.
TheHypervisorwillscheduletheRootPartitionvirtualprocessors(alongwithguestvirtualprocessors)intologicalprocessorsasitseesfit.
Thinkofthisasround-robinscheduling.
IfranasinglethreadedappontherootpartitionandusedprocessoraffinitywithintheRootpartitionOS,youwouldseealloftheCPUforthatapprunninginoneoftherootpartitionvirtualprocessors–justasyouwouldseefromthetaskmanagerinsidetherootpartition.
ButlookingattheHypervisorlayeryouwillseethattheloadwasactuallyspreadoutamongthelogicalprocessors!
Figure3-ExampleshowingHypervisorcallsOntheright,intheyellowarea,aretheactiveGuestVirtualMachines.
ThesealsohaveVirtualProcessors.
BoththeRootPartitionandGuestVMsvirtualprocessordisplaysshowCPUusagebrokenbetweenappropriateOSandHypervisorusage.
SeeFigure3foranexampleofthisYoushouldnotethatthetaskmanagerinsideguestOSmachineslies.
Thisisn'tthetaskmanager'sfault.
IntheexampleshowninFigure3,theWindowsTaskManagerwithintheguestoswouldbeshowing100%CPUutilizationwhereoursnapshotshowsonly90%.
Microsoftreferstothisasclockslew,butbasicallytheHypervisorispullingtherugoutfromundertheOS'snose(de-schedulingthevirtualprocessor)andtheOSdoesn'tknowit.
Thisiswhywemustpullinformationoutofthehypervisortoknowwhatisreallygoingon.
AlsonotehowtheheavyprocessinginsideofoneVMisbeingspreadbetweenmultiplevirtualprocessors.
ThiswilloccurevenifprocessoraffinityisusedintheVM,asisintheexampleFigure4.
Inthiscase,afullyconsumingsinglethreadedprocessstartedintheVMw7Beta-9-1,adual-processorVM.
Afterrunningforabout10seconds,weappliedprocessoraffinitytothesingle-threadedprocessFigure4-ExamplewithProcessorAffinityinsidetheVM,assigningitto(virtual)processor0.
AscanbeseenintheVMgraphs,theloadchangesfrombeingsplitbetweentheVMsvirtualprocessorstoconsumingonlyvirtualprocessor0,andyetatthehypervisorlevelweseenoeffectontheloadingofphysical(logical)processors.
ThishasimplicationsonrunningHyper-VonaNUMA(Non-UniformMemoryAccess)system.
IfyouareusingaNUMAhardwareplatformyoumightwanttoconsiderreadinguponappropriatetechniquestoassociateVMsandVMmemorytospecificNUMAgroups(c.
f.
"WindowsServer2008Hyper-VResourceKit",MicrosoftPress).
Withthistool,itiseasytounderstandwhyWindowsXPandearlierOSssignificantlyunderperformsonHyper-VincomparisontoWindowsServer2003,orVista,orabove.
Youwillseesignificantlymorehypervisor"overhead"processingwiththeolderoperatingsystemsbecauseMicrosoftmademodificationstotheneweroperatingsystemstobehypervisor(andprocessorVT)aware.
ThosenewerOSsdonotdisplaysuchbehavior.
Itisallintheenlightenments!
Inmysetup,itiscommontoseeheavyhypercallCPUusagewithheavyIOusageintheXPVMsasisseeninFigure5.
TheamountofoverheadyouseewithWindowsXPisnotlikelytobeashighasisshowninthisexample.
Thisisunderinvestigation(theremaybeaCPU/chiprevisionlevelinvolvedinmysetup),andiswhyImadethistoolinthefirstplace!
Figure5-WindowsXPHypervisorLoadExampleNewStuffInadditiontomakingthegraphsshowhistoricalinformationandtherollingaverageblueline,youcannowhoverthemouseoverbothgraphsandthemanytextsectionstoseemoredetailinformationin"tooltips".
Memoryrelatedinformationhasbeenadded,bothfortherootpartitionandtheVMs(whenWMI/RPCaccessisallowed).
ThisinformationisfocusedonthreekeyvaluestohelpyoudecideifyouhavetoomuchortoolittlememoryinstalledintheVM.
InstallindicatesthenumberofMegabytesphysicallyinstalledinthecaseoftherootpartition,orallocatedtotheVMinthecaseofVMs.
Availablememoryistheportionoftheinstalledmemoryconsidered"available"bytheOS(thetechnicaldefinitionofavailablememoryvariesinsomeOSs,butconsideritasmemoryavailabletoanapplicationondemandwithoutrequiringexistingmemorytobepagedout).
NotethatMemoryallocatedtorunningVMsarealsoshownasconsumedmemoryinthehostpartitionOS.
ThehostandVMpartitionsalsoshowthekeystatistic"PgIn/S".
Thisrepresentsthenumberofbytespersecondreadinfromthediskduetohardpagefaults.
Heavypagingactivityinthiscounterindicatestheneedformorememory.
Finally,someFileandTCPI/Ocountershavebeenaddedtotherootpartitiondisplay.
FileandnetworkI/Otogetherrepresentthethirdmajorperformanceconcernfortheserver(afterCPUandMemory).
LegaleseTheproductisfree;hasnosupport;isnotwarrantedforanyuse.
Feedbackisencouraged.
Giftsacceptedgratefully.