Described herein, are methods and devices for execution of a task in a grid computing system. According to an implementation, free time-slots are identified and durations of the free time-slots are estimated, by an edge device, for execution of a sub-task. The free time-slots are indicative of an idle state of the edge device. At least one computation capability parameter of the edge device is determined by the edge device for execution of a sub-task during the free time-slots. An advertisement profile having at least one free time-slot, and the duration and the at least one computation capability parameter associated with the at least one free time-slot is created by the edge device. The advertisement profile is provided by the edge device to grid servers in the grid computing system for partitioning a main task to create a sub-task executable by the edge device.