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Progress Report. 2014/05/30. Things to Do from Last Meeting. Check the number of thread of the media player and the loading of each thread. Only one thread. No conclusion yet… Define the objective and constraints of the virtual core scheduling problem. Scheduling Virtual Cores.
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Progress Report 2014/05/30
Things to Do from Last Meeting • Check the number of thread of the media player and the loading of each thread. • Only one thread. • No conclusion yet… • Define the objective and constraints of the virtual core scheduling problem.
Scheduling Virtual Cores • Every VM has a set of virtual cores. • The hypervisor schedules these virtual cores to physical cores for execution. • Current solution in Xen: Credit-based scheduler
Big.LITTLE Core Architecture • Difference between traditional SMP • Virtual cores can be either big or little. • Physical cores can be either big or little. • Should schedule virtual big core to only physical big cores in order to keep performance.
Virtual Core Scheduling Problem • For every time period, given a set of VMs, each VM has a set of virtual cores. • The operating frequency and type of each virtual core is known. • How to schedule these virtual cores to a set of big and little physical cores, such that the power consumption is minimal while keeping performance.
Objective • Schedule a set of virtual cores to physical cores, such that the power consumption is minimal. • Assume there are n physical cores.
Model • Virtual core vCi = {type, Vi} • type is either big or little. • Vi is the frequency from the virtual core. • Physical core corei = {type, freq, load, power(freq,load)} • typeis either big or little. • Power consumption of a core is a function of freq and load.
Constraints • Each virtual cores should be assigned with sufficient computing resources. • Assume there are m virtual cores. • Two sets of constraints
Constraints (I) • Find aj,i for each virtual core j with frequency Vj, such that • aj,i is the percentage of Vj on Coreifrom the perspective of virtual core j.
Constraints (II) • Find bi,jfor each virtual core j such that • bi,jis the percentage of time Coreiis executing virtual core j.
Other Constraints • Can set aj,i = 0/bi,j= 0 if core i and virtual core j are not the same type(big or little). • Limit the variation of resource assigned to each virtual core.
Things to Do • 2-page short paper for GCCE 2014 • 6/9 • Camera ready paper for ICPP 2014 • 6/15 • Full paper for ICPDAS 2014 • 7/1