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C Speed Optimization Checklist

This is a list of general-purpose optimizations for C programs, from the most impactful to the tiniest low-level micro-optimizations to squeeze out every last bit of performance. It is meant to be read top-down as a checklist, with each item being a potential optimization to consider. Everything is in order of speed gain.

Algorithm && Data Structures

Choose the best algorithm and data structure for the problem at hand by evaluating:

  1. time complexity
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julienbenjamin / KB-Buying-guide-EU.md
Created March 7, 2025 01:53 — forked from henfiber/KB-Buying-guide-EU.md
Buying keyboards and keyboard components from EU

Europe

  • SkinFlint : Price comparison site which has some nice filtering options per switch type etc. Searches for offers in UK, Germany, Poland and Austria
  • mykeyboard.eu : Keyboards, keycaps and accessories. Based in Belgium.
  • candykeys.com : European Store selling Vortex, Leopold, KBP, Anne Pro keyboards, keycap sets and components (ISO + ANSI). Based in Germany, ships to EU.
  • falba.tech : custom wooden bamboo cases, and some acrylic and carbon ones. Switch packs (65 browns at 48EUR). Other parts for the GH60, Atreus, ErgoDox. Also Microcontrollers, diodes, leds etc.
  • 42keebs.eu - Mostly PCBs, tools and accessories. Located in Czech Republic.
  • KEYGEM : Switches, Keycaps, lubes, cables, DIY kits and deskmats. Based in Germany, ships to the EU and worldwide.
  • [Eloquent Clicks - Custom Mechanical Keyboard Store](https://www.eloquen
@julienbenjamin
julienbenjamin / gmk87-manual.md
Created April 28, 2025 19:12 — forked from emanuellopes/gmk87-manual.md
GMK67 manual (English)

Conventional Commit Messages starline

See how a minor change to your commit message style can make a difference.

Tip

Take a look at git-conventional-commits , a CLI util to ensure these conventions, determine version and generate changelogs

Commit Message Formats

Default

@julienbenjamin
julienbenjamin / VAAPI-hwaccel-encode-Linux-Ffmpeg&Libav-setup.md
Created August 5, 2025 13:32 — forked from Brainiarc7/VAAPI-hwaccel-encode-Linux-Ffmpeg&Libav-setup.md
This gist contains instructions on setting up FFmpeg and Libav to use VAAPI-based hardware accelerated encoding (on supported platforms) for H.264 (and H.265 on supported hardware) video formats.

Using VAAPI's hardware accelerated video encoding on Linux with Intel's hardware on FFmpeg and libav

Hello, brethren :-)

As it turns out, the current version of FFmpeg (version 3.1 released earlier today) and libav (master branch) supports full H.264 and HEVC encode in VAAPI on supported hardware that works reliably well to be termed "production-ready".

@julienbenjamin
julienbenjamin / latency.txt
Created August 15, 2025 10:38 — forked from jboner/latency.txt
Latency Numbers Every Programmer Should Know
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