Patent ID: 7493439

Claim:
A method of providing performance monitoring, the method comprising: detecting the occurrence of selected bus conditions that occur within a hub device over time, the conditions characterized by type and the hub device in a cascade interconnect memory system; recording the number of detected events of each type in event counters, the recording performed by a performance monitor integrated within the hub device; recording the event counters and running sum values for each type in event frequency arrays along with the amount of time the event counters were active, wherein the event counters are selectively logged into the event frequency array based on two or more selectable conditions including after a programmed amount of time and an event counter reaching a threshold; sampling input addresses and a command stream received at the hub device using one or more a trace arrays, the command stream including one or more commands having indeterminate response times and including tag information for correlating a memory access request in the command to a memory access response to the command; recording one or more of the input addresses and the command stream; stopping the recording of the one or more of the input addresses and the command stream in response to receiving a stop trace signal; recording performance information for the commands having indeterminate data response times; and reporting the performance information for the commands having indeterminate data response times.