###### tags: `ubuntu` `geek` `undervolt`

# sf515_u1804_undervolt

under-volt and many other settings I tried
## to monitor my machine
### i7z
https://magiclen.org/linux-intel-cpu/
### top
already built-in
### htop
`sudo apt install htop`
### s-tui
https://github.com/amanusk/s-tui#ubuntu
`pip install s-tui`
#### optional utility to stress-test
to compute a lot to test the machine
`sudo apt-get install stress`

## under-volt
### kitsunyan/intel-undervolt
https://github.com/kitsunyan/intel-undervolt
https://miloserdov.org/?p=1932
https://wiki.archlinux.org/index.php/Undervolting_CPU
Yet to try.
Should to fine, according to some discussion.

### xdever/linux-intel-undervolt-tool
https://github.com/xdever/linux-intel-undervolt-tool
I tried this at the beginning.

It did work.

But now I want to delete it.
But it doesn't provide convenient way to uninstall.
I have to undo all the settings manually.

Not yet have the time to do so.

:::info
xdever/linux-intel-undervolt-tool uses bin/undervolt as the command name.
Unfortunately, georgewhewell/undervolt uses the same.
For a temporary solution, I did `sudo mv /usr/bin/undervolt /usr/bin/__undervolt` to let georgewhewell/undervolt (by pip) to take control of the name *undervolt*.
:::

:::info
georgewhewell/undervolt's `undervolt --read` confirms that xdever/linux-intel-undervolt-tool did change the voltage settings.
:::

### georgewhewell/undervolt
https://github.com/georgewhewell/undervolt
I ran `pip install undervolt`
But `OSError: [Errno 13] Permission denied: '/dev/cpu/0/msr'`
According to https://github.com/georgewhewell/undervolt/issues/46
I used `sudo $(which undervolt) -r` and it worked.

## Result
cpu -120 seems stable after tested
### TODO experiment #00
want to test

core: -120.12 mV
cache: -120.12 mV
analogio: 0.0 mV
uncore: 0.0 mV
gpu: 0.0 mV

by prime95
http://benjr.tw/99150

## TODO find a value for GPU

### TODO find some good gpu monitor
sudo apt install intel-gpu-tools
### TODO find some good gpu benchmarks
#### glmark2
sudo apt install glmark2
#### mesa-utils
sudo apt install mesa-utils

## TODO

try to do `cpu -120`
try to do `gpu -100`

find a way to let my machine ask me to set undervolt parameter only once after each login,
to avoid an unbootable machine

want to know what will happen for a too low undervolt for GPU

## Mar.28.2020 lastest notes

> just use `xdever/linux-intel-undervolt-tool`
>
> `git clone https://github.com/xdever/linux-intel-undervolt-tool`
> to somewhere such as `/york-tools/xdever_linux-intel-undervolt-tool_y56ed_in-use`
>
> `chmod +x install.sh`
>
> edit the `config.json` as
> ```
> {
> "cpu": -100,
> "gpu": -100
> }
> ```
>
> I have set up an alias in `.bashrc`
> ```
> # alias by `Y`ork for `U`nder`V`olt
> alias yuv='cd york-tools/xdever_linux-intel-undervolt-tool_y56ed_in-use/; sudo ./install.sh; cat config.json; cd'
> ```
> just use `sudo yuv` to do undervolting

###

use 'sudo pip install undervolt'
https://github.com/georgewhewell/undervolt
alias

# York under volt read
alias yuvr='sudo $(which undervolt) -r'