1、CSC 2228 ProjectCSC 2228 ProjectDynamic Voltage Dynamic Voltage Scaling in Mobile Scaling in Mobile DevicesDevicesDavid Tam,Winnie Tsang,Catalin DrulaDavid Tam,Winnie Tsang,Catalin DrulaWhat We Did?Implement DVS algs+develop our ownTarget:Linux 2.6&Intel P4-MWhy is this important?DVS goal=save energ
2、yExplore DVS algs on Linux 2.6&P4-M SpeedStepUsed hypothetical idle timesDeveloped new DVS alg with OS infoDVS alg:nAvgN*,PAST,PEAK,FUTUREArchitecture3 Components:CPUFREQ INTERFACE+DRIVERSOS SCHEDULER MODDVS Governorsset_speed()increase_speed()decrease_speed()AvgN*PastPeakFuturerun_cycles()idle_cycl
3、es()excess_cycles()DVS InterpretationGoal:stretch task to consume 99%of the given quantumNo major changes to schedulerBusyIdleGiven QuantumDVS ALGORITHMSFUTUREnOur own proposed algorithmnIdea:nLook into the run_queue:n Get hypothetical idle time in the futurenPrediction and Speed Setting is same as
4、PASTEXPERIMENTAL SETUPPlatform:nIBM Thinkpad T30nRedhat 9 2.6.0-test9 Linux kernel.nIntel Mobile Pentium 4-M processornUsed ACPI in Linux to measure capacity(mWh)Frequency(GHz)Voltage(V)1.61.31.21.2Idle-state-EXPERIMENTAL SETUPExperiments:nWorkload is 2m30sec long and consists of:nAn mpeg video runn
5、ing in the backgroundnSleep for 20 secondsnCompile Linux kernel(linking stage)nlasts 20-30 secondsnSleep for 20 secondsnSame compilation againEXPERIMENTAL RESULTSEnergy Usage020040060080010001200AlgorithmBattery Usage(mWh)High Speed(1.6 Ghz)Low Speed(1.2 Ghz)AvgN n=0,hysteresis 50-70,interval50AvgN
6、n=5,hysteresis 50-70,interval50Past,hysteresis 50-70,interval 1000Past,hysteresis 40-80,interval 1000Future,hysteresis 50-70,interval1000Future,hysteresis 40-80,interval1000Peak,interval 1000Peak,interval 500StaticAvgNPastFuturePeakEXPERIMENTAL RESULTSCompile Time05101520253035AlgorithmCompile Time(
7、s)High Speed(1.6 Ghz)Low Speed(1.2 Ghz)AvgN n=0,hysteresis 50-70,interval50AvgN n=5,hysteresis 50-70,interval50Past,hysteresis 50-70,interval 1000Past,hysteresis 40-80,interval 1000Future,hysteresis 50-70,interval1000Future,hysteresis 40-80,interval1000Peak,interval 1000Peak,interval 500StaticAvgNPa
8、stFuturePeakFUTURE WORKImplementation of excess cycleFine tuning DVS alg parametersMore workloadsNew DVS algsCONCLUSION&CONTRIBUTIONSBest policies are AVGn and PASTDVS algs on new OS&real hardwarenUsed hype idle times“Future”algContributions to Linux community:n4 governors for CPUFreqnMake available on web谢谢你的阅读v知识就是财富v丰富你的人生 Thank you
