[$] TurboSched: the return of small-task packing

CPU scheduling is a difficult task in the best of times; it is not trivialto pick the next process to run while maintaining fairness, minimizingenergy use, and using the available CPUs to their fullest potential. Theadvent of increasingly complex system architectures is not making thingseasier; scheduling on asymmetric systems (such as the big.LITTLEarchitecture) is a case in point. The "turbo" mode provided by some recentprocessors is another. The TurboSchedpatch set from Parth Shah is an attempt to improve the scheduler'sability to get the best performance from such processors.