1. A method for providing annotations to a target system for use in executing a code block, the method comprising: examining the code block to be annotated; identifying a hardware customization to support a specified quality of service level for executing the code block with a reduced energy expenditure; determining one or more annotations associated with the identified hardware customization; and providing the determined one or more annotations to the target system to cause the target system to execute the code block using the identified hardware customization.