Table 5 Performance evaluation of DVFS
Parameter(s) | Evaluation |
|---|---|
Performance | DVFS provide good performance, it reduces the instruction that processor issue in a particular instance of time therefore which results in power reduction |
Energy efficiency | Provide good energy efficiency if workload is known or dividing task and assigning different frequency. But still it’s better from static power management |
V and P relationship | As equation suggest that relationship between power and voltage is quadratic However, it might not be quadratic sometime linear and sometime nonlinear depend on interactions |
Complexity | DVFS architecture is much complex and sometime structure of the system also increase its complexity |
Cost (in terms of money) | The implementation of the same logic on chip is required huge efforts. Due to the technicalities involved it is costly |
Maintenance | At each instruction, the CPU frequencies need to be adjusted so it’s hard to operate and improvement and enhancement is not always easy |
Response time | RT consists of non-linearity but it’s executed fast so it provide better Response Time Sometime program execution is independent to cpu, I/O bound processes executed without CPU involvement |
Platform effect | It’s obvious that energy savings vary from platform to platform and infrastructure to infrastructure. It’s also varying with different hardware and software architecture |
Timeslots management | In this technique, if we are defining timeslots without considering any model like Round Robin then problems like starvation can occur some processes may exceeds their execution time and some processes might not get the fair share of CPU time |
User awareness | User Awareness is required to execute programs or implementing DVFS at compiler level. If a program is developed without paying any intention to energy may mislead toward bad results |
Cost (in terms of man power) | Lots of efforts are required to develop energy efficient system, which required a lot of programming skills and intention |
Workload | When workload is known, DVFS works well, but when workload is unknown then response is non-trivial |