Hardware Reference
In-Depth Information
Fig. 6.24
Example of Linux
load balancing
Time = T
CPU #0
CPU #1
2
1
CPU #2
CPU #3
0
3
The Linux load balancer migrates the
process of the penguin 0 from the
CPU #3 to CPU #2 to balance the
loads among four CPU cores.
Time = T + d
CPU #0
CPU #1
2
1
CPU #2
CPU #3
0
3
Table 6.4
Frequency-voltage relationship of RP-2
Highest frequency of four cores (MHz)
Voltage supplied (V)
600
1.4
300
1.2
150
1.0
75
1.0
The RP-2 Linux kernel supports DVFS with the CPUfreq framework. The RP-2
Linux kernel supports power gating with the CPU Hot-plug framework. Both
CPUfreq and CPU Hot-plug are controlled with the power control manager daemon
that realizes the “Idle Reduction” framework described in Sect. 5.1.2. The original
CPUfreq has the “ondemand,” “conservative,” “powersave,” “performance,” and
“userspace” governors which represent power management policies. The power
Search WWH ::
Custom Search