KLOS: A High Performance Kernel-Less Operating System

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 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 non-privileged. Our service call mechanism results in 28 clock cycles in the best case and 50 clock cycles in the average case which is an order of magnitude faster than current widely implemented methods of service or system