In the Big Data era, the volume of data is exploding, putting forward a new challenge to the existing computer system. Traditionally, the computer system is designed to be computing-centric, in which the data from IO devices are transferred and then processed by the CPU. However, the data movement is proved to be very expensive which can no longer be ignored at the Big Data era. To meet the ever-increasing performance need, we expect the computer system to be redesigned in the data-centric fashion. Different computing engines are deployed in different storage hierachies, including cache, memory and disk, to form a multi-level data processing system. By doing computation in the most appropriate data hierachy, the overall system performance and power efficiency are expected to be greatly improved.