joekur

Proper use of html_safe

Let's look at an innocuous piece of ruby. Consider some view code showing a user's name and phone number:

"#{first_name} #{last_name} #{phone}"

Great - this is very succinct, readable, and can easily be extracted to a method in a

benlesh

var app = angular.module('myApp', []);

/* Set up a simple controller with a few 
 * examples of common actions a controller function
 * might set up on a $scope. */
app.controller('MainCtrl', function($scope, someService) {
  
  //set some properties
  $scope.foo = 'foo';
  $scope.bar = 'bar';

seboudry

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns                     on recent CPU
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 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 4X memory

bokmann

# Thee will be more information here when I share the entire problem space I'm working on, but
# in short, this is preview material for my second talk in a series called "What Computer Scientists Know".
# The first talk is on recursion, and goes through several examples., leading up to a problem based
# on a simple puzzle that initial estimates based on performance of a previous puzzle would take years
# to solve on modern computers with the techniques shown in Ruby. That sets the stage for improving the
# performance of that problem with threading, concurrency, and related tuning.
#
# The second talk is on threading and concurrency, touching on algorithmic performance as well.
# Using some knowledge of the problem (board symmetry, illegal moves, etc), we reduce the problem space
# to about .5% of what we initially thought it was.  Still, the initial single threaded solution took more

BanzaiMan

$ jruby -v
jruby 1.7.5.dev (1.9.3p392) 2013-09-04 090d5dd on Java HotSpot(TM) 64-Bit Server VM 1.7.0_25-b15 [darwin-x86_64]
$ time jruby -J-XX:+TieredCompilation -J-XX:TieredStopAtLevel=1 -J-Xverify:none -e 'require "rails"'
jruby -J-XX:+TieredCompilation -J-XX:TieredStopAtLevel=1 -J-Xverify:none -e   5.18s user 0.47s system 136% cpu 4.142 total
$ time jruby -e 'require "rails"'                    
jruby -e 'require "rails"'  14.60s user 0.44s system 202% cpu 7.444 total