hellerbarde

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs

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.

---

dergachev

OS X Screencast to animated GIF

This gist shows how to create a GIF screencast using only free OS X tools: QuickTime, ffmpeg, and gifsicle.

Instructions

To capture the video (filesize: 19MB), using the free "QuickTime Player" application:

CMCDragonkai

Understanding the Memory Layout of Linux Executables

Required tools for playing around with memory:

• hexdump
• objdump
• readelf
• xxd
• gcore

JoeyBurzynski

58 bytes of CSS to look great nearly everywhere

When making this website, i wanted a simple, reasonable way to make it look good on most displays. Not counting any minimization techniques, the following 58 bytes worked well for me:

main {
  max-width: 38rem;
  padding: 2rem;
  margin: auto;
}

nrk

ffprobe -v quiet -print_format json -show_format -show_streams "lolwut.mp4" > "lolwut.mp4.json"

sleevi

On Twitter the other day, I was lamenting the state of OCSP stapling support on Linux servers, and got asked by several people to write-up what I think the requirements are for OCSP stapling support.

1. Support for keeping a long-lived (disk) cache of OCSP responses.

   This should be fairly simple. Any restarting of the service shouldn't blow away previous responses that were obtained. This doesn't need to be disk, just stable - and disk is an easy stable storage for most server

lavalamp

There are three easy to make mistakes in go. I present them here in the way they are often found in the wild, not in the way that is easiest to understand.

All three of these mistakes have been made in Kubernetes code, getting past code review at least once each that I know of.

1. Loop variables are scoped outside the loop.

What do these lines do? Make predictions and then scroll down.

func print(pi *int) { fmt.Println(*pi) }

GnaphronG

 #! /bin/sh
 
 file="bbb_sunflower_2160p_30fps_normal.mp4"
 timestamp=`date +%s`
 ffmpeg="docker run --rm -it --workdir /tmp -v $PWD:/tmp kynothon/moviola:4.0-alpine "
 bento4="docker run -it --rm -u $(id -u):$(id -g) -v $PWD:/tmp --workdir /tmp ggoussard/bento4docker "
 
 echo "Getting the file"
 curl -LO http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_2160p_30fps_normal.mp4
 

dtoma

#!/usr/bin/env python

"""Simple server using epoll."""

from __future__ import print_function
from contextlib import contextmanager
import socket
import select