I have really missed graphs of system status from android. I wanted something like you have in task manager on windows, or widgets on my KDE desktop. When I found nothing like that, I decided to write one, here it is.

Usemon is a simple application for monitoring usage of system resources. It displays graphs of CPU, RAM, and network usage. (For dual and quad core devices per core stats are supported.) No root needed. It is extremely lightweight, because it gets these data directly from the kernel. It can show permanent statusbar notifications of these too (when enabled). It support devices running android 4.0 and higher, thanks to that it integrates well into the holo themed system.

Features:
- Monitoring CPU, RAM, network and disk usage
- Every data is logged
- If the screen is off, battery usage is minimized
- It can show network download, and upload rate separately
- Widgets are included, they are capable of displaying CPU, RAM or network usage
- Statusbar notifcations you can check anytime
- Colored graphs makes it easy to identify witch graph represent the information you are looking for

Note about wakelock detectors:
Usemon will generate a large number of alarms (this is the way it works), thats normal, but it won't wake the device up from deep sleep. If something else wakes it up and the screen is off, Usemon won't do anything other than detecting that it is off.

Screenshots: