Date Added: Jan 2011
The emerging data-intensive applications of today are comprised of non-uniform CPU and I/O intensive workloads, thus imposing a requirement to consider both CPU and I/O effects in the power management strategies. Only scaling down the processor's frequency based on its busy/idle ratio cannot fully exploit opportunities of saving power. The authors' experiments show that besides the busy and idle status, each processor may also have I/O wait phases waiting for I/O operations to complete. During this period, the completion time is decided by the I/O subsystem rather than the CPU thus scaling the processor to a lower frequency will not affect the performance but save more power.