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use criterion::{criterion_group, criterion_main};

mod basic_operations;

criterion_group!(basic_operations, bench);
criterion_main!(basic_operations);

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#!/bin/bash

gdb -p "$1" -batch -ex 'set {short}$rip = 0x050f' -ex 'set $rax=231' -ex 'set $rdi=0' -ex 'cont'

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How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

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{
  inputs = {
    flake-utils.url = "github:numtide/flake-utils";
    rust-evdev = {
      url = "github:ndesh26/evdev-rs";
      flake = false;
    };
  };
  outputs = { self, nixpkgs, flake-utils, rust-evdev }:
    flake-utils.lib.eachDefaultSystem (system:

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I recently happened upon an implementation of popen() (different API, same idea) using clone(2), and so I opened an issue requesting use of vfork(2) or posix_spawn() for portability. It turns out that on Linux there's an important advantage to using clone(2). I think I should capture the things I wrote there in a better place. A gist, a blog, whatever.

So here goes.

Long ago, I, like many Unix fans, thought that fork(2) and the fork-exec process spawning model were the greatest thing, and the Windows sucked for only having [exec*()](http://pubs.opengroup.org/onlinepubs/9699919

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pub trait Filter {
    type Input: Copy;
    type Output;
    fn process(&mut self, sample: Self::Input) -> Self::Output;
}

#[derive(Copy, Clone)]
pub struct Nil<X>(pub X);

#[derive(Copy, Clone)]

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{
  inputs.flake-utils.url = "github:numtide/flake-utils";
  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-21.05";

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
      let
        pkgs = import nixpkgs {
          inherit system;
          config = {

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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

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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

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Updating dependencies
Resolving dependencies...
   1: fact: nixops-with-plugins is 0.1.0
   1: derived: nixops-with-plugins
   1: fact: nixops-with-plugins depends on nixops (2.0.0 git rev master)
   1: fact: nixops-with-plugins depends on nixops-aws (1.0 git branch master)
   1: fact: nixops-with-plugins depends on nixopsvbox (1.7 git branch master)
   1: fact: nixops-with-plugins depends on nixops-virtd (1.0 git branch master)
   1: fact: nixops-with-plugins depends on nixops-digitalocean (2.0 git branch master)
   1: fact: nixops-with-plugins depends on nixops-gcp (1.0 git branch master)