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

AWS Grok patterns for load balancer logs

Connection logs

https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-connection-logs.html#connection-log-entry-format

Sample logs:

2023-10-04T17:05:15.514108Z 203.0.113.1 36280 443 TLSv1.2 ECDHE-RSA-AES128-GCM-SHA256 4.036 "CN=amazondomains.com,O=endEntity,L=Seattle,ST=Washington,C=US" NotBefore=2023-09-21T22:43:21Z;NotAfter=2026-06-17T22:43:21Z FEF257372D5C14D4 Success

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:

	#!/usr/bin/env bash
	# Build a .zip compatible with AWS Lambda
	set -euo pipefail

	# operate from the same directory as this script
	SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
	cd "$SCRIPT_DIR"

	# By default create lambda.zip for Python 3.13 on amd64
	OUTPUT_ZIP="${OUTPUT_ZIP:-lambda.zip}"

	#!/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

	/**
	* Small helper script to debug via printing in WorldEdit CraftScript.
	* Save this file as debug.js in your WorldEdit config folder:
	* e.g. config/worldedit/craftscript/debug.js
	*
	* Use in the console:
	* /cs debug
	* /cs debug player
	*
	* With no arguments this script will print all globals.

	<?xml version="1.0" encoding="UTF-8"?>
	<LightBurnProject AppVersion="1.6.03" FormatVersion="1" MaterialHeight="0" MirrorX="False" MirrorY="False">
	<Thumbnail Source="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

	#!/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

Lee Trout leetrout

Latency numbers every programmer should know

AWS Grok patterns for load balancer logs

Connection logs

How to easily setup PXE boot for cluster provisioning

PXE boot description