Experimental ATM Network Interface Performance Evaluation

Traditional methods of measuring network interface performance have been based on throughputsensitive bench marks However the performance of an everincreasing number of applications depends on the latency and not on the throughput of the underlying communication network system Experimental performance evaluation of latency and its constituent parts for high speed network interfaces of personal computers has not been studied in depth to date We have developed performance evaluation methods that derive detailed PCI to ATM network interface latency results for personal computers based on a combined softwarehardware cooperation Our methods address the seamless data collection of events that have six orders of magnitude dierence in their duration and range from user level requests down to segmentation latencies for packets within the network interface As a result all steps which contribute to the total transmission latency have been accurately measured for a specic network interface type Experimental results derived with the new method are presented and its adaptation to vendor independent measurements is described Our experience suggests that measuring network interface latency using our methods is entirely feasible with equipment normally found in digital design laboratories Furthermore it may lead to a deep understanding of the underlying communication system which would be dicult if not impossible to acquire only with throughputsensitive benchmark