Mastering MySQL Database Architecture: Deep Dive into MySQL Shell and MySQL R...
Energy Efficient OS fo Android Powered Smart Devices
1.
2.
3. Android shipments reached 136 million
units in Quarter 3, 2012, which accounts for
75% of the 181.1 million shipments during
the quarter.
Most of the Android powered device got a
3.5”-5” screen, 3G connectivity, Wi-
fi, Bluetooth, 1GHz or higher processor, GPS
and more, which powered by 1500 MAh
battery.
4. We want to increase the battery life of the
smart devices but not to loose the
performance.
Android is based on Linux kernel, we have
got the opportunity to modify the kernel, so
we choose this platform.
5. Operating System
› Linux Mint for Compiling Source
Tools
› Bash script
› Google’s updater script
› SQLite database engine
6. Kernel governor and I/O scheduler
benchmark.
init.d tweak
GPS.conf tweak
Build.prof tweak
Odex and Deodex Rom
zRAM swap and zipalign.
SQLite auto sync off.
7. Since Android/Linux is multitasking
capable, CPU needs to share its cycles to
more than one running task. This is a job for
CPU governor.
Governors are especially important in smart
phones and tablets because they have a large
impact on the apparent fluidity of the
interface and the battery life of the device
over one time charge.
8. Different governors have different
parameters. Ideally, a governor will have-
› Sampling rate
› Threshold
Various tweak can be placed, and the
governor gives different battery
performance with due to various I/O
schedulers.
9. Kernel controls the disk access using I/O
scheduler.
Purpose of I/O scheduler:
› Minimize hard disk seek latency.
› Prioritize I/O requests from processes.
› Allocate disk bandwidth for running processes.
› Guarantee that certain requests will be served
before a deadline.
10.
11. Android boot-up process consists of the
following steps-
› At first the bootloader runs.
› Kernel boots and load various kernel objects(.ko
files) and prepare the hardware.
› User space programs are invoked. This is the
stage where the init.d script runs. Also various
apps and daemons are started to prepare the
Rom.
12. Most of the custom kernel supports init.d
script.
init.d script are to be placed inside
/system/etc/init.d directory (or
/etc/init.d which is a symbolic link to
/system/etc/init.d)
Order of executing init.d scripts are in the
increasing order of ASCII values that
corresponds to their names.
13.
14. build.prop is a properties file of android
operating system.
Battery performance can be improved by
changing build.prop properties like-
› Touch response
› 3G speed up
› Net speed tweak
› GPU rendering
› Wi-Fi signal tweak
15. GPS.conf twaek
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SQLite auto synchronization off
Odex and Deodex
Zipalign
zRAM swap