TaskFolder: Dynamic and Fine-Grained Workload Consolidation for Mobile Devices.

ABSTRACTDespite the resource-constrained environment associated with mobile devices, the Android task scheduler tries to spread the workload equally among all CPU cores. While this is a sensible use of resources in desktop or server environments, it is inefficient for mobile devices, because they usually have lower computing demand and require single-user-perceptible performance guaran-tees. As a result, spreading tasks to all cores does not improve per-formance, increases energy consumption, and can cause perfor-mance issues when multiple mobile virtual machines attempt to engage as many cores as possible. To address this problem, we propose TaskFolder, a multi-core management scheme implemented on top of the task scheduler. TaskFolder attempts to compute the minimum number of cores required to perform the current workload without sacrificing per-formance, and schedules tasks to only that minimal number of cores. This number is called the Core Concurrency and is calculated based on past task dynamics. Experimental results of a case study show that TaskFolder saves an average of 19% and up to 48% of CPU power over a set of mobile applications on the latest Intel mobile platform.