Patents

Method, apparatus, and system for energy efficiency and energy conservation including code recirculation techniques [abstract]
Jaewoong Chung, Youfeng Wu, Cheng Wang, and Hanjun Kim
US Patent App. 13/327,683, July 2012. [WO Patent App. PCT/US2012/069,236 and CN Patent App. 201,280,069,797 ]

An apparatus, method and system is described herein for enabling intelligent recirculation of hot code sections. A hot code section is determined and marked with a begin and end instruction. When the begin instruction is decoded, recirculation logic in a back-end of a processor enters a detection mode and loads decoded loop instructions. When the end instruction is decoded, the recirculation logic enters a recirculation mode. And during the recirculation mode, the loop instructions are dispatched directly from the recirculation logic to execution stages for execution. Since the loop is being directly serviced out of the back-end, the front-end may be powered down into a standby state to save power and increase energy efficiency. Upon finishing the loop, the front-end is powered back on and continues normal operation, which potentially includes propagating next instructions after the loop that were prefetched before the front-end entered the standby mode.