Bootchart updates

Bootcharting

------------

This version of init contains code to perform "bootcharting": generating log

files that can be later processed by the tools provided by <http://www.bootchart.org/>.

Bootchart provides CPU and I/O load breakdown of all processes for the whole system.

Refer to the instructions at

 <https://source.android.com/docs/core/perf/boot-times#bootchart>.

On the emulator, use the -bootchart _timeout_ option to boot with bootcharting

activated for _timeout_ seconds.

On a device:

    adb shell 'touch /data/bootchart/enabled'

Don't forget to delete this file when you're done collecting data!

The log files are written to /data/bootchart/. A script is provided to

retrieve them and create a bootchart.tgz file that can be used with the

bootchart command-line utility:

    sudo apt-get install pybootchartgui

    # grab-bootchart.sh uses $ANDROID_SERIAL.

    $ANDROID_BUILD_TOP/system/core/init/grab-bootchart.sh

One thing to watch for is that the bootchart will show init as if it started

running at 0s. You'll have to look at dmesg to work out when the kernel

actually started init.

def analyze_process_maps(process_map1, process_map2, jiffy_record):

    # List interesting processes here

    processes_of_interest = [

        '/init',

        '/system/bin/init',

        '/system/bin/surfaceflinger',

        '/system/bin/bootanimation',

        'zygote64',