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Latency Comparison Numbers (~2012)
----------------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

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My notes for Dokku on Digital Ocean.

These may be a bit outdated: Since I originally wrote them, I've reinstalled on a newer Dokku and may not have updated every section below.

Commands

Install dokku-cli (gem install dokku-cli) for a more Heroku-like CLI experience (dokku config:set FOO=bar).

# List/run commands when not on Dokku server (assuming a "henroku" ~/.ssh/config alias)

ssh henroku dokku

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Deploying Phoenix on Dokku

Worked 2015-09-08 for Phoenix 1.0.1 on Dokku 0.3.25.

These instructions assume you've set up Dokku. If not, go find a tutorial for that part. My notes for setting it up on Digital Ocean.

On your local machine, in the app's repo

Create a Dokku app:

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#!/bin/bash
set -euo pipefail

########################
### SCRIPT VARIABLES ###
########################

# Name of the user to create and grant sudo privileges
USERNAME=$0

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import sched, threading, time
from concurrent.futures import ThreadPoolExecutor
from math import ceil

class ThreadedScheduler:
    def __init__(self, f, delay=0, period=1, poolsize=2):
        # delay is initial delay from now until first schedule run
        # period is the amount of time between each call
        # though that probably still contains problems
        # if the time to run each call to f exceeds 1 second

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do

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#server numbers
from collections import defaultdict

def next_server_number(numbers):
    for i,n in enumerate(sorted(numbers), 1):
        if i != n:
            return i
    return len(numbers) + 1

def split_letter_digit(s):

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from string import digits, ascii_lowercase

int_to_base_36 = digits + ascii_lowercase
base_36_to_int = {v:k for k,v in enumerate(int_to_base_36)}

def largest_multiple(n, multiplier):
    print(type(n), type(multiplier))
    exp = 1
    while True:
        if multiplier**(exp+1) > n:

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from concurrent.futures import ThreadPoolExecutor
from time import sleep
from collections import Counter
from random import shuffle
from pprint import pprint

x = ThreadPoolExecutor(1000)
lst = list(range(10))
def sleepsort(l):
    sorted_l = []