How to install "System Load Indicator" in ubuntu 16.10
The System Load Indicator can be installed in Ubuntu 16.10 by adding the System Load Indicator stable daily builds PPA:
sudo add-apt-repository ppa:indicator-multiload/stable-daily
sudo apt update
Now you will be able to install it with any GUI package manager / software center or:
sudo apt install indicator-multiload
Please note it should also be available in the official Universe repository and can be installed with the command above without adding the daily PPA.
The reason why it doesn't show up in your software center is still unknown but it's likely to be solved by refreshing the software sources and installing the regular updates.
In Ubuntu 16.10 and later indicator-multiload is in the universe repository. Search the Software application for System load indicator. Alternatively you can also find the System load indicator by searching for the package's name (indicator-multiload). If System load indicator doesn't appear in the Ubuntu 16.10 Software app, this is a bug like this one: Missing package names in Ubuntu Software Center. It should be reported it as a new bug, since that bug was reported 4½ years ago and it happened when using a different application.
You an also download the .deb files for indicator-multiload for Ubuntu 16.10 manually.
- Download Page for indicator-multiload_0.4-0ubuntu4_amd64.deb on AMD64 machines
- Download Page for indicator-multiload_0.4-0ubuntu4_i386.deb on Intel x86 machines