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

thesamesam

FAQ on the xz-utils backdoor (CVE-2024-3094)

This is a living document. Everything in this document is made in good faith of being accurate, but like I just said; we don't yet know everything about what's going on.

Background

On March 29th, 2024, a backdoor was discovered in xz-utils, a suite of software that

fernandoaleman

Problem

Installing mysql2 gem errors on Apple silicon M1, M2 or M3 Mac running macOS Sonoma.

Solution

Make sure mysql-client, openssl and zstd are installed on Mac via Homebrew.

Replace mysql-client with whichever mysql package you are using

killercup

/*
 * I add this to html files generated with pandoc.
 */

html {
  font-size: 100%;
  overflow-y: scroll;
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
}

erikig

lukeplausin

# Count total EBS based storage in AWS
aws ec2 describe-volumes | jq "[.Volumes[].Size] | add"
# Count total EBS storage with a tag filter
aws ec2 describe-volumes --filters "Name=tag:Name,Values=CloudEndure Volume qjenc" | jq "[.Volumes[].Size] | add"
# Describe instances concisely
aws ec2 describe-instances | jq '[.Reservations | .[] | .Instances | .[] | {InstanceId: .InstanceId, State: .State, SubnetId: .SubnetId, VpcId: .VpcId, Name: (.Tags[]|select(.Key=="Name")|.Value)}]'
# Wait until $instance_id is running and then immediately stop it again
aws ec2 wait instance-running --instance-id $instance_id && aws ec2 stop-instances --instance-id $instance_id

# Get 10th instance in the account

AlD

debootstrap --arch=i386 --include=rrdtool stable /tmp/rrdtool-i386 &&
mount --bind /var /tmp/rrdtool-i386/var                            &&
find /var -mount -type f -name \*.rrd |
  while read rrd; do
    td=$(mktemp -d)
    linux32 chroot /tmp/rrdtool-i386 rrdtool dump "$rrd" > $td/xml &&
    rrdtool restore $td/xml $td/rrd                                &&
    cp $td/rrd "$rrd"
    rm $td/{xml,rrd}
    rmdir $td

vvalgis

set :rails_env, :production
set :unicorn_binary, "/usr/bin/unicorn"
set :unicorn_config, "#{current_path}/config/unicorn.rb"
set :unicorn_pid, "#{current_path}/tmp/pids/unicorn.pid"

namespace :deploy do
  task :start, :roles => :app, :except => { :no_release => true } do 
    run "cd #{current_path} && #{try_sudo} #{unicorn_binary} -c #{unicorn_config} -E #{rails_env} -D"
  end
  task :stop, :roles => :app, :except => { :no_release => true } do 

DavidGoodwin

#!/bin/bash
# -*- sh -*-

: << =cut

=head1 NAME

Munin plugin to plot Linux CPU pressure - see: https://lwn.net/Articles/759781/

=head1 CONFIGURATION

mguterl

#!/bin/sh
set -u
set -e
# Example init script, this can be used with nginx, too,
# since nginx and unicorn accept the same signals

# Feel free to change any of the following variables for your app:
APP_ROOT=/home/deploy/public_html/rm/current
PID=$APP_ROOT/tmp/pids/unicorn.pid
ENV=production