How do we gauge performance?

There are different lenses through which we can assess the performance of a system. A common approach is to equate the overall system performance with the speed of the processor. If go back to simpler times when single-processor systems were the order of the day and compare them with modern multi-socket, multi-core systems, we’ll see that the processor performance has increased by, to put it simply, an epic proportion. If we compare the improvement factor for processor performance with that of a disk, the processor is a runaway winner.

The response times for storage devices are usually measured in milliseconds. For processors and memory, that value is in nanoseconds. This results in a state of incongruity between the application requirements and what the underlying storage can actually deliver. The performance of the storage subsystem has not progressed at the same rate. Therefore, the argument about equating system performance with processor...