Analysis and measurement of the effect of kernel locks in SMP systems

This article reports the use of case studies to evaluate the performance degradation caused by the kernel‐level lock. We define the lock ratio as a ratio of the execution time for critical sections to the total execution time of a parallel program. The kernel‐level lock ratio determines how effective programs work on symmetric multiprocessor (SMP) systems. We have measured the lock ratios and the performance of three types of parallel programs on SMP systems with Linux 2.0: matrix multiplication, parallel make, and WWW server programs. Experimental results show that the higher the lock ratio of parallel programs, the worse their performance becomes. Copyright © 2001 John Wiley & Sons, Ltd.