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

steven2358

FFmpeg cheat sheet

A list of useful commands for the FFmpeg command line tool.

Download FFmpeg: https://www.ffmpeg.org/download.html

Full documentation: https://www.ffmpeg.org/ffmpeg.html

Basic conversion

ityonemo

A half-hour to learn Zig

This is inspired by https://fasterthanli.me/blog/2020/a-half-hour-to-learn-rust/

Basics

the command zig run my_code.zig will compile and immediately run your Zig program. Each of these cells contains a zig program that you can try to run (some of them contain compile-time errors that you can comment out to play with)

djspiewak

Quick Tips for Fast Code on the JVM

I was talking to a coworker recently about general techniques that almost always form the core of any effort to write very fast, down-to-the-metal hot path code on the JVM, and they pointed out that there really isn't a particularly good place to go for this information. It occurred to me that, really, I had more or less picked up all of it by word of mouth and experience, and there just aren't any good reference sources on the topic. So… here's my word of mouth.

This is by no means a comprehensive gist. It's also important to understand that the techniques that I outline in here are not 100% absolute either. Performance on the JVM is an incredibly complicated subject, and while there are rules that almost always hold true, the "almost" remains very salient. Also, for many or even most applications, there will be other techniques that I'm not mentioning which will have a greater impact. JMH, Java Flight Recorder, and a good profiler are your very best friend! Mea

bkaradzic

Orthodox C++

What is Orthodox C++?

Orthodox C++ (sometimes referred as C+) is minimal subset of C++ that improves C, but avoids all unnecessary things from so called Modern C++. It's exactly opposite of what Modern C++ suppose to be.

Why not Modern C++?

devhero

Byobu is a suite of enhancements to tmux, as a command line
tool providing live system status, dynamic window management,
and some convenient keybindings:

  F1                             * Used by X11 *
    Shift-F1                     Display this help
  F2                             Create a new window
    Shift-F2                     Create a horizontal split
    Ctrl-F2                      Create a vertical split
    Ctrl-Shift-F2                Create a new session

joepie91

No, your cryptocurrency cannot work

Whenever the topic of Bitcoin's energy usage comes up, there's always a flood of hastily-constructed comments by people claiming that their favourite cryptocurrency isn't like Bitcoin, that their favourite cryptocurrency is energy-efficient and scalable and whatnot.

They're wrong, and are quite possibly trying to scam you. Let's look at why.

What is a cryptocurrency anyway?

There are plenty of intricate and complex articles trying to convince you that cryptocurrencies are the future. They usually heavily use jargon and vague terms, make vague promises, and generally give you a sense that there must be something there, but you always come away from them more confused than you were before.

terrancesnyder

#! /bin/sh
# ==================================================================
#  ______                           __     _____
# /_  __/___  ____ ___  _________ _/ /_   /__  /
#  / / / __ \/ __ `__ \/ ___/ __ `/ __/     / /
# / / / /_/ / / / / / / /__/ /_/ / /_      / /
#/_/  \____/_/ /_/ /_/\___/\__,_/\__/     /_/

# Multi-instance Apache Tomcat installation with a focus
# on best-practices as defined by Apache, SpringSource, and MuleSoft

gtallen1187

"Scar Tissues Make Relationships Wear Out"

04/26/2103. From a lecture by Professor John Ousterhout at Stanford, class CS142.

This is my most touchy-feely thought for the weekend. Here’s the basic idea: It’s really hard to build relationships that last for a long time. If you haven’t discovered this, you will discover this sooner or later. And it's hard both for personal relationships and for business relationships. And to me, it's pretty amazing that two people can stay married for 25 years without killing each other.

[Laughter]

> But honestly, most professional relationships don't last anywhere near that long. The best bands always seem to break up after 2 or 3 years. And business partnerships fall apart, and there's all these problems in these relationships that just don't last. So, why is that? Well, in my view, it’s relationships don't fail because there some single catastrophic event to destroy them, although often there is a single catastrophic event around the the end of the relation

kdrnic

kdrnic's Caves of Qud beginner notes

The guide below I wrote mostly for myself as a "notebook" of info I found, but then slightly expanded it with stuff that may be useful to others.

As of finishing writing, I have 16 hours of CoQ playtime and have a level 20 character, definitelly still a beginner as well, perhaps a slightly seasoned beginner.

My previous roguelike experience included beating DCSS with a minotaur berserker and playing a good amount of POWDER on my celphone.

Justification

The game is a tad opaque. As this Qud denizen explains (I don't agree with his overall opinion):