Northeast PHP - High Performance PHP

August 11th, 2012High Performance PHP Northeast PHP 2012 Jonathan Klein jonathan.n.klein@gmail.com @jonathanklein

Agenda Who am I? Why Performance Matters Profiling PHP Applications Code Level Optimizations Big Wins Load Testing Takeaways

Introduction• Web Performance Platform Lead at Wayfair• Boston Web Performance Meetup Group Organizer• Led a team that converted most of Wayfair’s storefront codebase from Classic ASP to PHP. 1. Rewrote ~100,000 lines of code• Wayfair Stats: 1. 450 reqs/sec for dynamic content (PHP pages) 2. 1600 reqs/sec for static content (including CDN) 3. Codebase has > 400,000 lines of PHP (some is 3rd party) 3

The Value of Performance

Real World Examples• Firefox: -2.2 seconds = 15.4% more downloads• Shopzilla: -5 seconds = 7-12% increase in revenue• Google: +400ms = 0.76% fewer searches• Amazon: +100ms = -1% revenuehttp://www.phpied.com/the-performance-business-pitch/ 6

80/20 Rule 80% of page load time takes place on the client 7

We’re going to talk about the other 20%

A fast page load is 2 secondsThis means you have 400ms to get that HTML off your server

But network time could be ~100msThis means you have 400ms 300ms to build the page

The average length of an eye blink is 100-400 milliseconds Full Page Load – 2 Seconds Base HTML – 400ms Server Generation Time – 300ms

Profiling PHP Applications Monitoring and Tracing

Monitoring/Tracing Tools• Paid: 1. Tracelytics (bought by AppNeta) 2. AppDynamics (building a PHP solution) 3. dynaTrace (building a PHP solution 4. New Relic• Free: 1. StatsD/Graphite 2. Xdebug 3. Nagios 4. Ganglia 13

Monitoring/Tracing Tools• Paid: 1. Tracelytics (bought by AppNeta) 2. AppDynamics (building a PHP solution) 3. dynaTrace (building a PHP solution 4. New Relic• Free: 1. StatsD/Graphite 2. Xdebug 3. Nagios 4. Ganglia 14

StatsDUDP Packets – extremely low overhead<?php$start = microtime(true);…script content…$end = microtime(true);MyStats::timing(foo.bar, $end - $start);?>http://codeascraft.etsy.com/2011/02/15/measure-anything-measure-everything/ 15

Graphite• Written by Orbitz• Real-time graphing engine for StatsD data (among other things)• http://graphite.wikidot.com/• Architecture: http://www.aosabook.org/en/graphite.html 16

Xdebug• PHP extension (need to install) - http://xdebug.org/• Code level tracing 1. Exposes hotspots• Significant overhead, use in DEV only!• Add ?XDEBUG_PROFILE=true to a URL• View results: 1. kcachegrind on linux 2. wincachegrind on Windows 20

Lesson: Profile Your Code

Code Level Optimizations

Writing Efficient PHP• Set max value before loop: $max = count($rows); for ($i = 0; $i < $max; $i++) { echo $i; }• require_once() is slow• Minimize use of define()• Yes, single quotes are slightly faster than double quotes 27

Almost Every Micro-Optimization is Worthless

http://phpbench.com/

Writing Efficient PHP• Set the max loop value before the loop: $max = count($rows); for ($i = 0; $i < $max; $i++) { echo $i; } Okay, this one is pretty good 32

So Why Even MentionMicro-Optimizations?

Lesson: Focus on the Big Wins“Premature optimization is the root of all evil” - Donald Knuth

Big Wins

Upgrade PHP 5.3 is ~20% faster than 5.2 http://news.php.net/php.internals/36484 5.4 is ~20-40% faster than 5.3 http://news.php.net/php.internals/57760 Upgrading 5.2  5.4 gives a 45-70% improvement! http://php.net/migration53 http://php.net/migration54 38

PHP 5.4 is 5 Times Faster than PHP4 http://static.zend.com/topics/White-paper-PHP4-PHP5.pdf

Use APC (Correctly) APC – Alternative PHP Cache 40

Opcode Cache Performance• Vanilla settings  30-40% improvement• Turn off APC Stat  additional ~2x improvement! -- Understand what is happening herehttp://www.slideshare.net/vortexau/improving-php-application-performance-with-apc-presentation 41

APC User Cache<?php$bar = Hello World!;apc_store(foo, $bar);?><?phpvar_dump(apc_fetch(foo));?>-------- Output --------string(12) "Hello World!" 42

APC User Cache Optimizations• Avoid fragmentation - keep utilization under 10% 1. Assign 1GB, only fill 100MB• Compress objects that are > 10KB before storing• Reduce garbage collection in the source of apc_store()• Consider CDB 1. http://engineering.wayfair.com/moving-constants-out-of-apc-and-into-cdb/ 43

Caching• Avoid hitting the database• Cache in APC/Memcached• 1:00 tomorrow: “Caching With Memcached” 44

Fix All Errors• PHP 5.3: E_ALL | E_STRICT• PHP 5.4: E_ALL• Can also do error_reporting(-1); 45

Child Processes• 4-6 processes per CPU core.• Beyond that just add servers. (Test your app) 46

HipHop for PHP• Developed/Open Sourced by Facebook• Transforms PHP source code into highly optimized C++• Reduces CPU for Facebook’s servers by 50%http://developers.facebook.com/blog/post/2010/02/02/hiphop-for-php--move-fast/https://github.com/facebook/hiphop-php 47

Load Testing

JMeter• Open Source• Generate load via a GUI or command line• Can watch req/s peak out• Easy to use (just make sure you set the correct path to Java on your computer). 49

Be Careful• JMeter looks a lot like a DOS attack• Make sure you know what is failing• Look at monitoring while test is running• Run in Production• Run a test, make a change, run it again 55

Takeaways

“How Fast Is Your Site?”

This is a terrible question

Why is it terrible?• Lack of context• Are we talking about average or a percentile?• Server side time or client?• Who is measuring it?• When is it being measured?• Real users or synthetic? 59

We still have to answer it

Pick Tight SLAs“The homepage of our site will load in<300ms at the 80th percentile, measuredby sampling 10% of our real users over a24 hour period every day at 8AM.” 61

Pick Tight SLAs“The homepage of our site will load in<300ms at the 80th percentile, measuredby sampling 10% of our real users over a24 hour period every day at 8AM.” 62

Things to Remember1. Measure and monitor your application2. Focus on big wins3. Run the latest (stable) version of PHP4. Make sure you are using APC correctly5. It’s always the database: go to “The Proper Care and Feeding of a MySQL Database” talk6. Caching is your friend: go to the “Caching With Memcached” talk7. Know what system resources you depend on 63

There is a lot more

Get In Touchhttp://www.meetup.com/Web-Performance-Boston/ wayfair.com/careers jonathan.n.klein@gmail.com @jonathanklein 65

http://www.scoop.it	33
http://localhost	14
https://twitter.com	6
https://si0.twimg.com	3
https://twimg0-a.akamaihd.net	1

Northeast PHP - High Performance PHP

by Jonathan Klein on Aug 11, 2012

Accessibility

Categories

Upload Details

Usage Rights

5 Embeds 57

Statistics

Northeast PHP - High Performance PHP Presentation Transcript