STRATUS: Assembling Virtual Platforms from Device Clouds

There is an increasing number of network-enabled computing devices in homes and offices, driven by continued improvements in device capabilities and network connectivity. By exploiting the virtualization technologies that have begun to pervade even the mobile domain, these devices -- hardware components, such as displays, input devices, disks, or processors, can be decoupled from the physical platforms on which they reside to form a resource pool or device cloud. By drawing on the composite resources of device clouds, applications can leverage the heterogeneity present in the cloud to exploit hardware/device differences in terms of power consumption, computational speeds, display sizes, or the presence of certain accelerators, and can take advantage of software diversity in terms of the different operating environments and applications that efficiently operate on individual devices. This paper implements and evaluates the concept of device clouds, in which virtual execution platforms dynamically composed from sets of devices are built for applications, using automated methods that are based on simple policies. Experimental results identify the basic overheads associated with device clouds and their use, and demonstrate the advantages of dynamically constructed virtual platforms rather than individual machines, both in terms of improvements in system properties like power usage and improvements in user experiences for media delivery and play out.