Chapter 5: Energy Flashcards
What are 3 things why we care about Energy
- Its Expensive
- There is a finite amount available
- Money saved in energy usage can be allocated to the other things
What are 3 difference between Computers and Energy Efficient
- As the enterprise grows, its need for server power grows
- Increasing server power means increasing electrical cost to run the server
- According to IBM, it costs more over 3 years to run and cool a data centre than to actually buy it.
How is power used in percentages?
- 45% of the total data centre energy usage goes to server, storage and network equipment
- 55% goes to the server power and cooling
How much procceor does a server use?
5.1 pg 52 [84]
30%
How much does Power supply, memory, fans, planner driver etc use on a server hardware?
5.1 pg 52 [84]
70%
How much does a server load use?
5.1 pg 52 [84]
80% idle, 20% Resource usage rate
What is Throttling State?
[Class notes]
T-states will further throttle down a CPU, but not the actual clock rate, by inserting STPCLK (stop clock) signals and thus omitting duty cycles.
What is Power Capping
T-State meaning that sets the upper limit in watts that the server will use
What is P-State (performance state)?
Works by reducing clock rate. The slower the CPU the less voltage
What is T-states - throttling states
5.1 pg 56 [89]
T-states will further throttle down a CPU, but not the actual clock rate, by inserting STPCLK (stop clock) signals and thus omitting duty cycles.
The T-state mechanism works by “gating-off” clock ticks to the processor core. The processor clock always ticks at a fixed rate, but one or more tick in
every group of 8 ticks may be masked from the processor.
What is P-states - performance states?
5.1 pg 56 [89]
P-states allow clock rate reduction. The P-state mechanism involves actually slowing the clock down so that it ticks less frequently (rather than just masking off ticks). When the processor is run at a slower speed, the voltage to the processor can be reduced as well.
What is P-states is controlled by?
5.1 pg 56 [89]
the operating system.
What does Intel Xeon processors incorporate into P-State?
5.1 pg 56 [89]
Demand Based Switching (DBS) with Enhanced Intel Speedstep Technology. DBS, which is
operating system-dependent, is included in all dual, quad, and 6-core Xeon processor-based System x and BladeCenter servers.
What is C-states - Sleep states?
5.1 pg 57 [90]
C-states allow the clock to be halted.
The C-states mechanism works via different levels of sleep states. When the CPU is active, it always runs at C0, meaning that the CPU is 100% turned on.
What is Power capping?
5.1 pg 58 [91]
This refers to setting a specific power limit in terms of a fixed number of watts that the system should not exceed. Active Energy Manager will throttle the system to keep power from going higher than this limit.
