doc: update README

Author: Lauric Desauw

README.md

@@ -1,16 +1,16 @@
-VirtualWatts is a software-defined power meter based on the PowerAPI toolkit.
-VirtualWatts a configurable software that can estimate the power consumption of
-process inside a VM in real-time.
-VirtuallWatts is supposed to be used inside a VM. It need to receive two metrics :
+# Procfs-Sensor
 
-- The energy consumption of the VM, usually made with
-  [SmartWatts](https://github.com/powerapi-ng/smartwatts-formula)
-- The cpu usage of the tracked processes and the global cpu usage, as provided
-  by [procfs-sensor](https://github.com/powerapi-ng/procfs-sensor).
+The Proc Filesystem Sensor is a tool that monitor the CPU usage of cgroup via
+the linux's proc filesystem.
+It use `pidstat` to retreive the percentage of CPU usage of each process.
+It then use the `/sys/fs/perf_event` directory to find the appartenance of
+processes to cgroup.
+
+The sensor need the cgroup version 1. The version 2 is not supported yet.
 
 # About
 
-VirtualWatts is an open-source project developed by the [Spirals research
+Procfs Sensor is an open-source project developed by the [Spirals research
 group](https://team.inria.fr/spirals) (University of Lille 1 and Inria).
 
 The documentation is not available yet.
@@ -19,13 +19,13 @@ The documentation is not available yet.
 
 If you would like to contribute code you can do so through GitHub by forking the
 repository and sending a pull request.
-You should start by reading the [contribution guide](https://github.com/powerapi-ng/virtualwatts/blob/main/contributing.md)
+You should start by reading the [contribution guide](https://github.com/powerapi-ng/procfs-sensor/blob/main/contributing.md)
 
 When submitting code, please check that it is conform by using `pylint` and
 `flake8` with the configurations files at the root of the project.
 
 ## Acknowledgments
 
-VirtualWatts is written in [Python](https://www.python.org/) (under [PSF
-license](https://docs.python.org/3/license.html)) and built on top of
-[PowerAPI](https://github.com/powerapi-ng/powerapi)
+Procfs Sensor is written in [Python](https://www.python.org/) (under [PSF
+license](https://docs.python.org/3/license.html)).
+It also use [`pidstat`](https://github.com/sysstat/sysstat)