RealNeGate

// Compile with clang or MSVC (WINDOWS ONLY RN)
//
// Implementing a POC green threads system using safepoints to show how cheap and simple it can
// be done, all you need to do is call SAFEPOINT_POLL in your own language at the top of every
// loop and function body (you can loosen up on this depending on the latency of pausing you're
// willing to pay). Safepoint polling is made cheap because it's a load without a use site
// which means it doesn't introduce a stall and pays a sub-cycle cost because of it (wastes resources
// sure but doesn't block up the rest of execution).
//
//  # safepoint poll

IshaanAdarsh

Google Summer of Code 2023 Final Work Product

Introduction

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.

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.

pervognsen

// This can grow a Robin Hood linear probing hash table near word-at-a-time memcpy speeds. If you're confused why I use 'keys'
// to describe the hash values, it's because my favorite perspective on Robin Hood (which I learned from Paul Khuong)
// is that it's just a sorted gap array which is MSB bucketed and insertion sorted per chain:
// https://pvk.ca/Blog/2019/09/29/a-couple-of-probabilistic-worst-case-bounds-for-robin-hood-linear-probing/
// The more widely known "max displacement" picture of Robin Hood hashing also has strengths since the max displacement
// can be stored very compactly. You can see a micro-optimized example of that here for small tables where the max displacement
// can fit in 4 bits: Sub-nanosecond Searches Using Vector Instructions, https://www.youtube.com/watch?v=paxIkKBzqBU
void grow(Table *table) {
	u64 exp = 64 - table->shift;
	// We grow the table downward in place by a factor of 2 (not counting the overflow area at table->end).

creativcoder

// Blog post: https://creativcoder.dev/merge-k-sorted-arrays-rust

// Merge 2 sorted arrays
fn merge_2(a: &[i32], b: &[i32]) -> Vec<i32> {
    let (mut i, mut j) = (0, 0);
    let mut sorted = vec![];
    let remaining;
    let remaining_idx;
    loop {
        if a[i] < b[j] {

keichan34

function fish_greeting
  echo "! COMPUTER_NAME"
end

set -x EDITOR vim
set -x LESS -asrRix8

set -x LANG en_US.UTF-8
set -x LC_ALL en_US.UTF-8
set -x LANGUAGE en_US.UTF-8

pkhuong

import math
import struct
import unittest
import hypothesis.strategies as st
from hypothesis.stateful import Bundle, RuleBasedStateMachine, consumes, invariant, multiple, precondition, rule


class VarianceStack:
    def __init__(self):
        self.n = 0

kentonv

As tested on Linux:

• An SCM_RIGHTS ancillary message is "attached" to the range of data bytes sent in the same sendmsg() call.
• However, as always, recvmsg() calls on the receiving end don't necessarily map 1:1 to sendmsg() calls. Messages can be coalesced or split.
• The recvmsg() call that receives the first byte of the ancillary message's byte range also receives the ancillary message itself.
• To prevent multiple ancillary messages being delivered

causal-agent

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <sys/mman.h>
#include <unistd.h>
#include <err.h>
#include <sysexits.h>

typedef int32_t (*fptr)(int32_t);