Metadata-Version: 2.1
Name: pcvis
Version: 0.3.0
Summary: 2022-12-01
Author: Yue Ni
Author-email: niyue.com@gmail.com
Requires-Python: >=3.6,<4.0
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: 3.8
Classifier: Programming Language :: Python :: 3.9
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Description-Content-Type: text/markdown

# pcvis
A command line tool for visualizing page cache of a given file

# prerequisites
* install `pcstat` (Page Cache stat: get page cache stats for files, https://github.com/tobert/pcstat)
  * it has both Linux and macOS binaries since v0.0.1

# installation
## via `pip`
```
pip install pcvis
```
After installation, there will be a command called `pcvis` you can use
## manual
1. Download this repo, copy the `pcvis/pcvis.py` from this repo
2. Move `pcvis.py` into your `$PATH` (e.g. `/usr/local/bin`)
```
mv pcvis.py /usr/local/bin/pcvis
chmod +x /usr/local/bin/pcvis
```

# usage
Visualize a given file's page cache status like below. In the visualized image, the white dots indicate the part of the file that is in the page cache.

```
# pcstat still needs to be installed, and it will be automatically launched by pcvis
pcvis -f /path/to/my_file
```


## sample outputs
█░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░█░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░█░░░░░░░░░░░░░░░░░░░░█░░░░░░░░░█░░░░█░█░██░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░█

Via this visualization, you can easily spot that:
1. this file's header and footer are accessed and loaded in page cache
2. this file is accessed in a random access manner, and you may even vaguely check if the random access is a binary search, etc

## arguments
* `-f` or `--file`: the path to the file you want to visualize its page cache status, e.g. `pcvis -f /path/to/my_file`. If you specify this argument, `pcvis` will launch `pcstat` automatically and visualize the result. If this argument is not specified, `pcvis` will read the output of `pcstat` from `stdin`, e.g. `pcstat -json -pps /path/to/my_file | pcvis`
* `-s` or `--style`: there are over 20 different rendering styles to choose from, you can specify a custom style by passing an integer to this argument. The default style is `0`. Some sample styles are shown below:

  * e.g. `pcvis -s 24`
🌕🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌕🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌕🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌕🌑🌑🌑🌑🌑🌑🌑🌑🌑🌕🌑🌑🌑🌑🌕🌑🌕🌑🌕🌕🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌑🌕

  * e.g. `pcvis -s 17`
💚🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍💚🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍💚🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍💚🤍🤍🤍🤍🤍🤍🤍🤍🤍💚🤍🤍🤍🤍💚🤍💚🤍💚💚🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍🤍💚

* `-h` or `--help`: show help message


# notes
1. Before running the above command for visualization, you need to clean page cache so that the above result is accurate

```
# for linux
sync; echo 1 > /proc/sys/vm/drop_caches 
# for macOS
sudo purge
```

2. Some of the icons in the visualization requires UTF8 to render, so you may need to set locale to UTF8 under some systems
```
export LC_ALL="en_US.utf8"
```



