Eka Puji Widiyanto ekapujiw2002

Moved to git repository: https://github.com/denji/nginx-tuning

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

(from https://www.scivision.co/numpy-image-bgr-to-rgb/)

Numpy / OpenCV image BGR to RGB

Conversion between any/all of BGR, RGB, and GBR may be necessary when working with Matplotlib expects M x N x 3 image, where last dimension is RGB.

OpenCV expects M x N x 3 image, where last dimension is BGR.

Scientific Cameras, some of which output an M X N x 3 image, where last dimension is GBR

How to create self-signed SSL certificates for localhost

Option 1

Create a directory in your user root directory where we will store the necessary generated files.

$ cd ~/
$ mkdir .localhost
$ cd .localhost

Now run this single command and you will have both a certificate and private key which was used to sign the certificate.

Setup Alpine Linux

Make Disk Image

dd if=/dev/zero bs=1M of=disk.img count=1000

Formating Disk Image

cat <<EOF | sfdisk disk.img

Sample config for 2 million web socket connection

    sysctl -w fs.file-max=12000500
    sysctl -w fs.nr_open=20000500
    # Set the maximum number of open file descriptors
    ulimit -n 20000000

    # Set the memory size for TCP with minimum, default and maximum thresholds 
 sysctl -w net.ipv4.tcp_mem='10000000 10000000 10000000'

	import cv2
	import socketio #python-socketio by @miguelgrinberg
	import base64

	sio = socketio.Client()
	sio.connect('http://x.x.x.x:xxxx)

	cam = cv2.VideoCapture(0)

	while (True):

	#!/usr/bin/env python
	"""
	Ever had a mysqldump of utf8 data stored in latin1 tables, dumped in utf8 and
	munged with windows cp1252?

	If so this is your friend. Just pipe it through this little baby and spare
	yourself hours of unicode hell- it'll take your dirt and spit out clean utf8.

	You can also import it and use it in your python code.

	#/bin/sh
	#
	# Setup Kiosk mode for Alpine Linux
	#
	#!/bin/sh

	USER=kiosk
	KEYBOARD_LAYOUT=fr
	KEYBOARD_MODEL=mac
	WIDTH=1024

	---
	METHOD 1

	This should roughly sort the items on distance in MySQL, and should work in SQLite.
	If you need to sort them preciser, you could try using the Pythagorean theorem (a^2 + b^2 = c^2) to get the exact distance.
	---
	SELECT *
	FROM table
	ORDER BY ((lat-$user_lat)(lat-$user_lat)) + ((lng - $user_lng)(lng - $user_lng)) ASC

	# Exporting entire database:
	mysqldump -u user -p database --opt \| gzip > database.sql.gz

	# Export table
	mysqldump -uroot --opt --databases DB_NAME --tables TABLE_NAME \| gzip > /tmp/TABLE_NAME.export.sql.gz

	# Importing:
	gunzip < database.sql.gz \| mysql -u user -p database

	# Credit http://failshell.io/mysql/using-gzip-and-gunzip-with-mysql-to-importexport-backups/