mattyoho

Passing TCP socket descriptors around

In linux, normally, it is impossible to "bind()" to the same TCP port twice. If you try to bind to the same port from second proces unix processes you'll see:

socket.error: [Errno 98] Address already in use

mattyoho

Latency Comparison Numbers
--------------------------
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
Send 1K bytes over 1 Gbps network        10,000   ns    0.01 ms
Read 4K randomly from SSD*              150,000   ns    0.15 ms

mattyoho

1. General Background and Overview

• Probabilistic Data Structures for Web Analytics and Data Mining : A great overview of the space of probabilistic data structures and how they are used in approximation algorithm implementation.
• Models and Issues in Data Stream Systems
• Philippe Flajolet’s contribution to streaming algorithms : A presentation by Jérémie Lumbroso that visits some of the hostorical perspectives and how it all began with Flajolet
• Approximate Frequency Counts over Data Streams by Gurmeet Singh Manku & Rajeev Motwani : One of the early papers on the subject.
• [Methods for Finding Frequent Items in Data Streams](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.187.9800&rep

mattyoho

class CanHazRoutes
  include ActionController::UrlWriter

  host = case ENV['RAILS_ENV']
    when "production"
      "prod.com"
    when "staging"
      "stage.com"
    when "development"
      "app.local"

mattyoho

trials = []
10000.times{ trials << rand(6) }
trials.uniq.map do |u|
  trials.select { |t| t.equal? u }.size
end.collect do |c|
  c.to_f / trials.size
end

mattyoho

#!/bin/sh

REPO=$1
git clone $REPO
cd `basename $REPO .git`
for BRANCH in `git branch -r`; do
  git co --track \
         -b remote/$BRANCH \
            $BRANCH
done

mattyoho

#!/usr/bin/env ruby 
puts "looking for the gems to upgrade..."
gem_info = Struct.new(:name, :version)
to_reinstall = []
Dir.glob('/Library/Ruby/Gems/**/*.bundle').map do |path| 
  path =~ /.*1.8\/gems\/(.*)-(.*?)\/.*/
  name, version = $1, $2
  bundle_info = `file path`
  to_reinstall << gem_info.new(name, version) unless bundle_info =~ /bundle x86_64/
end

mattyoho

irb(main):054:0> class Cat
irb(main):055:1>   def eigen
irb(main):056:2>     class << self
irb(main):057:3>       self
irb(main):058:3>     end
irb(main):059:2>   end
irb(main):060:1> end
=> nil
irb(main):061:0> c1 = Cat.new
=> #<Cat:0x1017562d0>

mattyoho

[user@host ~]$ cat /proc/7128/cmdline
/usr/java/java/bin/java-Djava.awt.headless=true-Xms128M-Xmx256M-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager-Djava.util.logging.config.file=/usr/local/tomcat/conf/logging.properties-Djava.endorsed.dirs=/usr/local/tomcat/common/endorsed-classpath:/usr/local/tomcat/bin/bootstrap.jar:/usr/local/tomcat/bin/commons-logging-api.jar-Dcatalina.base=/usr/local/tomcat-Dcatalina.home=/usr/local/tomcat-Djava.io.tmpdir=/usr/local/tomcat/temporg.apache.catalina.startup.Bootstrapstart

mattyoho

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