USING COST TO CONTROL INSTRUMENTATION OVERHEAD

We present a new data collection cost system that provides programmers with feedback about the impact data collection is having on their app lication. We allow programmers to define the level of perturbation the ir application can tolerate, and then regulate the amount of instrumen tation to ensure that the threshold is not exceeded. Our approach is u nique in that the type of data gathered remains constant; instead, we regulate when data are collected. This permits programmers to trade sp eed of isolation of a performance problem for less application perturb ation. We implemented this cost system in the Paradyn Performance Tool s and present several case studies demonstrating the accuracy of the c ost system. (C) 1998-Elsevier Science B.V. All rights reserved.