A High Performance Kernel-Less Operating System Architecture

Operating Systems provide services that are accessed by processes via mechanisms that involve a ring transition to transfer control to the kernel where the required function is performed. This has one significant drawback that every service call involves an overhead of a context switch where processor state is saved and a protection domain transfer is performed. However, as we discovered, it is possible, on processor architectures that support segmentation, to achieve a significant performance gain in accessing the services provided by the operating system by not performing a ring transition. Further, such gains can be achieved without compromising on the separation of the privileged components from the unprivileged. KLOS is a Kernel-Less Operating System built on the basis of such a design. The KLOS service call mechanism is an order of magnitude faster than the current widely implemented mechanisms for service or system calls with a 4x improvement over the traditional trap/interrupt and a 2x improvement over the Intel SYSENTER/SYSEXIT fast system call models.