XRAY: Instrumentation for multiple computers

XRAY presents a global view of the performance of hardware and software components on multiple, distributed computers. The set of components chosen for measurement can be changed at any time throughout a network of systems, and can be selected to minimize data collection time and measurement space. In the course of normal activities the operating system executes firmware which increments counters for the measured components. Periodically, the counters are recorded in an ordinary file by a process in each processor. An analysis program permits browsing through components and plotting counters in real time. Analysis focuses on detecting the distributed sources of excessive activity.