The Android Development Tools (ADT) is a massive project and is very well done. Getting your hands on and compiling the Android Open Source Project (AOSP) is very easy too. So easy, you’ll quickly want to improve your compile performance. An initial compile of AOSP can take about ~46 minutes on an Intel i7 @ 3.4 GHz. Using the compile cache will definitely speed up sequential builds but more can still be done. Sacrificing just a few MB of RAM (~60 MB) for a system temp directory (/tmp) ramdisk can reduce compile time anywhere from ~2%-10% depending on total system throughput (other hardware specs). The C/C++ compiler creates, writes and deletes a temporary file for each source file crunched. Keeping this I/O traffic in RAM offers efficiency gains.
PC Desktop i7 @ 3.4 GHz x 8 w/16 GB RAM and 7200 RPM Drive
Without Ramdisk: ~44 minutes
With Ramdisk: ~41 minutes
Reduction in time playing swords: ~7%
PC Laptop Intel Core 2 Duo CPU T8300 @ 2.4 Gz x 2 w/4 GB RAM and 5600 RPM Drive
Without Ramdisk: 705 minutes
With Ramdisk: 650 minutes
Reduction in time playing swords: ~8%
To setup your /tmp directory to be a ramdisk on Ubuntu systems add the following to your /etc/fstab file and reboot
ramdisk /tmp tmpfs mode=1777,size=2g
There are two quick ways to make sure the ramdisk is working.
1) run the ‘df’ command and confirm /tmp is mounted with the correct size
2) copy a large file to your home directory and again to the /tmp directory and compare speeds
chris@chis-devpc:~/ServerBackups$ time cp 2012.11.04.04.00.MySQL_Backup.sql.gz ~/ real 0m2.657s user 0m0.000s sys 0m0.240s chris@chis-devpc:~/ServerBackups$ time cp 2012.11.04.04.00.MySQL_Backup.sql.gz /tmp real 0m0.224s user 0m0.000s sys 0m0.140s
The file copied above is 208MB. As you can see, the ramdisk was an order of magnitude faster.