jboner

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

josevalim

# Elixir v1.0
defmodule Rules do
  defmacro __using__(_) do
    quote do
      import unquote(__MODULE__)
      @before_compile unquote(__MODULE__)
      @rules []
    end
  end

staltz

The introduction to Reactive Programming you've been missing

(by @andrestaltz)

---

This tutorial as a series of videos

If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.

---

bitwalker

defmodule Config do
  @moduledoc """
  This module handles fetching values from the config with some additional niceties
  """

  @doc """
  Fetches a value from the config, or from the environment if {:system, "VAR"}
  is provided.

  An optional default value can be provided if desired.

sandeepraju

#!/bin/bash
# file: ttfb.sh
# curl command to check the time to first byte
# ** usage **
# 1. ./ttfb.sh "https://google.com"
# 2. seq 10 | xargs -Iz ./ttfb.sh "https://google.com"

curl -o /dev/null \
     -H 'Cache-Control: no-cache' \
     -s \

michiel

Nest/Lift

Nest 1

[INPUT]
    Name mem
    Tag  mem.local

[OUTPUT]

Name stdout

kddnewton

Faster Rails tests

Feedback loop speed in one of the biggest contributing factors to overall development time. The faster you get results, the faster you can move on to other things. A fast enough test suite is therefore critical to teams' success, and is worth investing some time at the beginning to save in the long run.

Below is a list of techniques for speeding up a Rails test suite. It is not comprehensive, but should definitely provide some quick wins. This list of techniques assumes you're using minitest, but most everything should translate over to rspec by simply replacing test/test_helper.rb with spec/spec_helper.rb.

• Lead with data
• bcrypt
• bootsnap
• Cache Time::utc calls

shakna-israel

Let's Destroy C

I have a pet project I work on, every now and then. CNoEvil.

The concept is simple enough.

What if, for a moment, we forgot all the rules we know. That we ignore every good idea, and accept all the terrible ones. That nothing is off limits. Can we turn C into a new language? Can we do what Lisp and Forth let the over-eager programmer do, but in C?

---

sts10

A curated list of command-line utilities written in Rust

Note: I have moved this list to a proper repository. I'll leave this gist up, but it won't be updated. To submit an idea, open a PR on the repo.

Note that I have not tried all of these personally, and cannot and do not vouch for all of the tools listed here. In most cases, the descriptions here are copied directly from their code repos. Some may have been abandoned. Investigate before installing/using.

The ones I use regularly include: bat, dust, fd, fend, hyperfine, miniserve, ripgrep, just, cargo-audit and cargo-wipe.

• atuin: "Magical shell history"
• bandwhich: Terminal bandwidth utilization tool