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

pkhuong

#!/usr/bin/env sed -re s|^|\x20\x20\x20\x20| -e s|^\x20{4}\x23\x23{(.*)$|<details><summary>\1</summary>\n| -e s|^\x20{4}\x23\x23}$|\n</details>| -e s|^\x20{4}\x23\x23\x20?|| -e s|\x0c|\x20|

license, imports

# Yannakakis.py by Paul Khuong
#
# To the extent possible under law, the person who associated CC0 with
# Yannakakis.py has waived all copyright and related or neighboring rights
# to Yannakakis.py.

carelvwyk

func buildEmailInput(source, destination, subject, message string,
	csvFile []byte) (*ses.SendRawEmailInput, error) {

	buf := new(bytes.Buffer)
	writer := multipart.NewWriter(buf)

	// email main header:
	h := make(textproto.MIMEHeader)
	h.Set("From", source)

jFransham

Achieving warp speed with Rust

Contents:

• Number one optimization tip: don't
• Never optimize blindly
• Don't bother optimizing one-time costs
• Improve your algorithms
• CPU architecture primer
• Keep as much as possible in cache
• Keep as much as possible in registers

mitchellh

//! Implements a texture atlas (https://en.wikipedia.org/wiki/Texture_atlas).
//!
//! The implementation is based on "A Thousand Ways to Pack the Bin - A
//! Practical Approach to Two-Dimensional Rectangle Bin Packing" by Jukka
//! Jylänki. This specific implementation is based heavily on
//! Nicolas P. Rougier's freetype-gl project as well as Jukka's C++
//! implementation: https://github.com/juj/RectangleBinPack
//!
//! Limitations that are easy to fix, but I didn't need them:
//!

josephg

In case anyone else wants to play with Zig on webassembly, here's what you need to do to make it work on a mac today.

1. Get LLVM 7 compiled with webassembly support.

You'll need LLVM to output to the WASM target. This has just been added by default in trunk, so if LLVM >7 is available, you might be able to just brew install llvm.

If you have wasm support already you should see:

$ llc --version

redblobgames

// SFC32 random number generator, public domain code adapted
// from https://github.com/bryc/code/blob/master/jshash/PRNGs.md
function PRNG(seed: number): {
    nextInt(): number;
    nextFloat(): number;
    getState(): number[];
    setState(state: number[]): void
} {
    let a = 0, b = seed, c = 0, d = 1;
    function sfc32() {

lynaghk

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;  Solo freelancer's S-Corp tax optimization
;;
;;  Assumes an unmarried single-shareholder and tons of other stuff.
;;  I'm not a tax professional, no guarantees here, probably typos, etc. Come on!
;;  Run with https://github.com/Z3Prover/z3
;;
;;  See also my notes at https://kevinlynagh.com/financial-plan/

klauspost

"  </div>"
"  })();\r\n"
" && "
" &amp; "
" &nbsp;"
" ''The "
" (&quot;"
" (199"
" (200"
" (e.g."

pervognsen

# I happened to be looking at some of Cranelift's code, and I noticed that their constant-time dominates()
# check was using a somewhat more ad-hoc version of a hidden gem from the data structures literature called the
# parenthesis representation for trees. As far as I know, this was invented by Jacobson in his 1989 paper
# Space-Efficient Static Trees and Graphs. I first learned about it from the slightly later paper by Munro and Raman
# called Succinct Representations of Balanced Parentheses and Static Trees. I figured I'd give it an extremely
# quick intro and then show how it leads to a (slightly better) version of Cranelift's algorithm.
#
# This parenthesis representation of trees is surprisingly versatile, but its most striking feature is that
# it lets us query the ancestor relationship between two nodes in a tree in constant time, with a few instructions.
# And the idea is extremely simple and intuitive if you just draw the right kind of picture.