kylix

OS:  Lubuntu 14.04 64-bit
HW: i7-2620M, 16GB RAM

As building android on a laptop, the cpu frequency often scales within 4xx MHz and 2.x GHz. But I wish cpu to run at full speed to solve time for building. After digging google, I finally find the available way as below.

1. Get "acpi-cpufreq" driver.    sudo apt-get update
    sudo apt-get install acpi-support acpid acpi

2. Get the tools for configing the cpu frequency.
    sudo apt-get install indicator-cpufreq
    sudo apt-get install cpufreqd cpufrequtils

3. Disable "intel_pstate" driver.
    sudo vim /etc/default/grub
        GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" -> "quiet splash intel_pstate=disable"
    sudo update-grub

4. Setup the minimal cpu frequency. (optional)
    sudo apt-get install sysfsutils
    sudo vim /etc/sysfs.conf
        Add "/devices/system/cpu/cpu0/cpufreq/scaling_min_freq = 1500000"
        If cpu has 8 cores, replace cpu0 with cpu1 ~ cpu7

Reference: Frequency scaling