1. A programmable logic device (PLD), comprising: a plurality of programmable hardware units coupled to a configuration bus, each of the programmable hardware units configurable with one of a plurality of functional modes; a plurality of switch devices to independently select one or more configuration patterns from a set of configuration patterns, each of the switch devices corresponding to one of the programmable hardware units; a plurality of configuration registers coupled to the configuration bus and commonly shared by the plurality of programmable hardware units, the configuration registers storing the set of configuration patterns, where each configuration patterns correspond to one of the plurality of functional modes of the programmable hardware units; one or more of the plurality of programmable hardware units accessing one of the configuration patterns, via the configuration bus, from a selected one of the configuration registers for configuration with the configuration pattern retrieved from the selected configuration register; and a runtime system controller to simultaneously schedule updating the configuration patterns in the plurality of configuration registers and access the configuration patterns from the plurality of configuration registers to configure the plurality of programmable hardware units.