Lee Trout leetrout

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

How to easily setup PXE boot for cluster provisioning

This guide will show you how to setup a PXE boot server to provision a cluster of machines. For the sake of this guide, we will be using system agnostic docker containers to simulate the DHCP and the PXE boot server.

Featured technologies:

PXE boot description

This was a response to a Hacker News comment asking me what I've been up to since 2010. I'm posting it here since HN rejects it with "that comment is too long." I suppose that's fair, since this ended up being something of an autobiography.

--

What happened after 2010?

This is a Gistified version of https://gist.github.com/hfreire/5846b7aa4ac9209699ba#gistcomment-2833377

	// all the example arns from this page: http://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html
	var arns = [
	'arn:aws:elasticbeanstalk:us-east-1:123456789012:environment/My App/MyEnvironment',
	'arn:aws:iam::123456789012:user/David',
	'arn:aws:rds:eu-west-1:123456789012:db:mysql-db',
	'arn:aws:s3:::my_corporate_bucket/exampleobject.png',
	'arn:aws:artifact:::report-package/Certifications and Attestations/SOC/*',
	'arn:aws:artifact:::report-package/Certifications and Attestations/ISO/*',
	'arn:aws:artifact:::report-package/Certifications and Attestations/PCI/*',
	'arn:aws:autoscaling:us-east-1:123456789012:scalingPolicy:c7a27f55-d35e-4153-b044-8ca9155fc467:autoScalingGroupName/my-test-asg1:policyName/my-scaleout-policy',

	#!/bin/bash

	# Run PXE boot server on interface
	# Seems to work with UEFI and Secureboot
	# Spip, 2023
	#
	# Most stuff from https://www.youtube.com/watch?v=E_OlsA1hF4k
	#

	# Check args

	#!/bin/bash

	# Credit to https://gist.github.com/alisdair/ffc7c884ee36ac132131f37e3803a1fe for the excellent original
	# script that this one is based on. This script modifies the original to create the all-the-way-down effect.

	# Generate a `:*-all-the-way-down:` Slack emoji, given a reasonable image
	# input. I recommend grabbing an emoji from https://emojipedia.org/

	set -euo pipefail

	#!/bin/bash

	# Credit to https://gist.github.com/alisdair/ffc7c884ee36ac132131f37e3803a1fe for the excellent original
	# script that this one is based on. This script modifies the original to create the jumbo.

	# Generate a jumbo Slack emoji, given a reasonable image
	# input. I recommend grabbing an emoji from https://emojipedia.org/

	set -euo pipefail

	#!/bin/bash

	# Generate a `:something-party:` Slack emoji, given a reasonable image
	# input. I recommend grabbing an emoji from https://emojipedia.org/

	set -euo pipefail

	if [ $# -eq 0 ]; then
	echo "Usage: $0 input.png"
	exit 1