The performance of operating system (OS) plays a significant role on the overall performance of embedded systems. The OS performance measurement can give a clear insight into the operating system behavior, which provides quite useful information in finding the bottlenecks in overall system design. This paper compares and analyzes the performance of various key features, which includes context switching time, synchronization time, Inter Process Communication (IPC) time and thread/process creation time, of two operating systems such as LEO (LSI Embedded Operating System) and the publicly available embedded Linux. The performance of both LEO and Embedded Linux is measured by keeping the hardware same. Experimental results are presented for both operating systems running on an ARM11 MPCore platform.