Copyright by William Lloyd Bircher 2010 - The Laboratory for ...

Core Power
power is dominated by leakage power since active power is low. Leakage power is
mostly affected by p-state changes. Fluctuations in IPC occur at much shorter durations
(100s ns) than p-state changes (100s ms). Therefore, stable power consumption levels
are less likely as the number of active cores increases.
60W
50W
40W
30W
20W
10W
0W
-10W
4.3 Summary
Phases due
to 10ms
scheduling 11%
quanta 15%
9%
10%
7%
11%
17% 28% 13%
8%
21%
12%
9%
64%
Figure 4.9 Core Power Phases – SYSmark 2007
This section characterizes power consumption in modern server and desktop computing
systems. The characterization demonstrates the relationship between the power
consumption of various subsystems and workloads. Popular computational workloads
such as SPEC CPU are shown to generate power variation in the processor and memory
subsystems, but not in the remainder of subsystems. By comparing power variation in a
server system with little power management to a recent desktop system with extensive
62
Active
Program
Phases
35%
12% 8%
12% 17% 11% 22%
1 10 100 1,000 10,000
Phase Duration (ms)
3D
E-Learning
Productivity
Video Creation
Relative size
correspond to %
samples in group
Idle Phases