In my current term, we are developing a web application that must run on an embedded system. The embedded system uses the Ubuntu operating system, and both the CPU and memory are limited. During development, we faced a performance issue, but we did not really where it came from. Initially, we used Linux’ “top” command to investigate the performance problem. However, this tool did not help us because it lacked details and the refresh rate wasn’t fast enough. So, we then began to use a tool that one of my colleagues found: nmon. The tool provides a mini GUI. It also gives us more details on CPU and memory usage. 
nmon allowed us to target more specifically the problem (i.e. the browser being used). Indeed, the browser, Firefox not to name it, used twice as much memory than other browsers. The solution to our problem: Google Chrome. So, if you ever need to investigate performance problems, I strongly urge you to use nmon or change browser.
