One example of a software stack is depicted in FIG. 4A. Such a stack may typically be used in traditional computing environments. In the stack shown in FIG. 4A, an application (402) sits above a database engine (404), which in turn sits upon an operating system (406), underneath which lies hardware (408). FIG. 4B depicts a software stack used in some embodiments. As with the stack shown in FIG. 4A, an application (452) sits above a database engine (454), which in turn sits upon an operating system (456). However, underneath the operating system and above the hardware is a layer of software (referred to herein as a hyper-kernel) that observes the system running in real time and optimizes the system resources to match the needs of the system as it operates. The hyper-kernel (one example of a virtual machine manager) conceptually unifies the RAM, processors, and I/O (Input Output resources for example Storage, Networking resources) of a set of commodity servers, and presents that unified set to the operating system. Because of this abstraction, the operating system will have the view of a single large computer, containing an aggregated set of processors, memory, and I/O. As will be described in more detail below, the hyper-kernel optimizes use of resources. The hyper-kernel can also help optimize other I/O system resources such as networks and storage. In some embodiments, based on observations and profiles of running software, performance indicators (hints) are provided to upper layers (e.g., database management systems) about the dynamic performance of the system that can further improve overall system performance.
