Profiling PHP
Applications
July 2011 - Justin Carmony
#uphpu
wifi: C7bluffdale -- c7dcguest

About Me
• CTO of Dating DNA
• CIO of CEVO LLC
• Make Websites & iPhone Apps
• Worked on Websites for Dell, nVidia,
DirectTV, and other big clients.

Experience
• Lots of work with “Middle-Scale” websites.
• Lucky to Work on Fun Projects
• Lots of Web Service Stuff
• Learned most of this from other really
smart people.

We’ll Use An Example
and an awesome one at that...

We Have Similar Jobs
Awesome, huh?

MythBusters
• They get a Myth
• Break it down to its
different parts
• They Conduct a Bunch
of Tests
• They Draw Conclusions
• and have a Fun Time

Developers
• We get Myths
(Hey, this is slow)
• We Break it down to
the different pieces
• We Conduct a Bunch of
Tests.
• We Draw Conclusions
(and normally make
changes)
• and Have a Fun Time...

So Lets Get Started!
php /lets/get/started.php now

First Off, Some
PHP Myths
and there are a lot of them!

Common Performance
Claims (Myths)
• echo instead of print() • single quotes, not double
quotes
• echo commas, not
periods • include instead of
include_once
• don’t use custom
functions/classes • === faster than ==
• pass by reference • for faster than foreach
instead of by value

To Quote
Derick Rethans
Author of Xdebug...

“I can only say one thing about this....
Complete & Utter
Bull****”

or in MythBusters Terminology....

I’m Serious, There are a
LOT of these Myths
These Example Came from Google’s Top 10 results for
“php performance tips”

These “Performance
Tips” Rarely Make a
Difference

Thats Like Debating the Windshield Wipers’s
Effect on this Car’s Performance

Intuition Based
Optimizations
i.e. how to not effectively
improve performance
Phrase Coined by Dave Smith
http://thesmithfam.org/blog/2011/02/

Your Intuitions are
WRONG
90% of the time

Example:
Fuel Efficiency Myths

MythBusters Tested
• Keeping Your AC Off vs Windows Down
• Idling Better than Stop/Start
• Magical Aerodynamics
• Dirt-Free Filters
• Special Fuel Additives to Slow Burn
All Busted! They Didn’t Make a Difference,
Or Worsened Fuel Efficiency

How About
Driving Angry?
After Testing, Tory & Grant Used
33% More Fule While Driving Angry

Effective Profiling
is based on
Actual Results

There are Two Types
of Profiling “Modes”

Normal Profiling
Lets Try this Configuration Change
and Measure the Performance Difference

Emergency Profiling
Aaaaaaaaaaaaah the Website is Down!!!!
Why is it so slow??? Fix it!!!!!!

Same Techniques
Apply to Both
• Some you’ll want to chose first depending
on your situation.
• You’ll want to be careful when profiling in
Production, you can make things worse.

Understanding the
Full Picture

Browser Static Files
Database and/or
Data Store
Web Server
PHP App
Server OS
Web Services &
Resources Hardware
Cache

Don’t Panic!

Goal: Find Slow Parts
aka Bottlenecks

Profiling & Testing
Different Parts

Tools!

Browser Static Files
Database and/or
Data Store
Web Server
PHP App
Server OS
Web Services &
Resources Hardware
Cache

FireBug

FireBug

Google Page Speed

Other Tools
• YSlow
http://developer.yahoo.com/yslow/
• Pingdom Tools
http://tools.pingdom.com/
• WireShark / Fiddler2

Browser Static Files
Database and/or
Data Store
Web Server
PHP App
Server OS
Web Services &
Resources Hardware
Cache

apachetop
apachetop -f /var/log/apache/example.com.access.log

Apachetop works
with nginx

Apache’s mod_status
<Location /server-status>
SetHandler server-status
Order Deny,Allow
Deny from all
Allow from 25.131.42.122
</Location>
# ExtendedStatus On

Apache’s mod_status

siege

siege
• Command Line Tool
• Run Concurrent HTTP Requests
• Runs on Linux & Mac OS
• Windows Users: Run a VM
• Great Way to Test End Result

siege
• Create txt file with lists of URLs to hit
• Run Command:
siege -c 10 -r 10 -f urls.txt
• c = concurrent
r = # of requests
f = path to URL file

siege

siege

Other Tools
• nginx stub status (similar to mod_status)
http://wiki.nginx.org/HttpStubStatusModule
• Apache Bench & http_load -- CLI
• JMeter -- Java Desktop App

Browser Static Files
Database and/or
Data Store
Web Server
PHP App
Server OS
Web Services &
Resources Hardware
Cache

My Favorite New Tools:
XHProf & XHGui

XHProf
• Developed by Facebook
• Works well for both Development
& Production* Profiling
• pecl extension
• Decent UI for viewing Results
* - Use Sampling & Special CPU Flags for Production
http://mirror.facebook.net/facebook/xhprof/doc.html

XHGui
• Improved GUI
• Easy to Setup
• Built In Sampling
• Advanced Configuration
• MySQL Backend
• I recommend using this!
https://github.com/preinheimer/xhprof

More Fun to Show
Demo Time

Xdebug Profiler
• Install Xdebug
• Enable Xdebug Profiling
• Outputs a Cachegrind Log
• Use KCachegrind / WinCachegrind /
Webgrind to view
• For the Rich, MacCallGrind for $150

Enabling Xdebug
Profiling
xdebug.profiler_enable=1
xdebug.profiler_output_dir=/tmp
xdebug.profiler_output_name=cachegrind.out.%p
Xdebug Profiling Not for Production
(unless you have a 100TB HDD laying around)

Webgrind

Timing Points
• Most Frameworks have Built-In Profiling /
Timing Points
• Most ORMs have them as well
• You can do them yourself
• A must for Database Queries

Timing Points
$start = microtime(true); // true to get as float
/* Do your Crazy Code, i.e. query */
$end = microtime(true);
$time = round($end - $start, 4);

Other Tools
• Inclued
http://php.net/manual/en/book.inclued.php
• Memtrack
http://php.net/manual/en/
book.memtrack.php

Browser Static Files
Database and/or
Data Store
Web Server
PHP App
Server OS
Web Services &
Resources Hardware
Cache

Databases
• Typically, First Thing to Slow Down
• Things to that will Kill the DB:
• Missing Indexes
• Nested Queries
• Large Joins
• Locked Queries

Jet Profiler
• MySQL Profiler
• Free Version (Okay) & Paid (Awesome)
• Not Cheap ($399)
• But Worth It
• Analytics Over Time

Jet Profiler

MySQL Commands
• explain <query>
• show processlist
• show variables
• show status

mtop

Browser Static Files
Database and/or
Data Store
Web Server
PHP App
Server OS
Web Services &
Resources Hardware
Cache

vmstat
command: vmstat 1

vmstat
• swap > 0 means swapping
Memory Issue
• cpu sys + us really high
CPU / Code / PHP Problem
• cpu wa > 10
Disk IO Problem*
* - Technically could be Network IO as well, but typically
one of the last and more rare bottlenecks to hit

vnstat
command: vnstat -l -i eth0

top

htop

strace

iotop

Other Tools
• netstat
• iostat
• mpstat
• pidstat
• (on ubuntu, install via sysstat package)

Other Tools
• grep, awk, sed
• IPs Connected:
netstat -plan | grep :80 | awk '{print $5}' |
sed 's/::ffff://g' | awk -F: '{print $1}' | sort |
uniq -c | sort -n

Monitoring
Munin
http://munin-monitoring.org/

Monitoring
Wormly
http://wormly.com/

Whew, Lots of Tools
and a lot more out there not in this talk
Find any cool ones, let me know!

Normal Profiling
• Start with XHProf/XHGui and FireBug
• Avoid Premature Optimization
• Complicated Change
• Little Reward
• Use siege, or alternative, to simulate load.

Emergency Profiling
• Start with OS Level Testing Tools (htop,
vmstat, vnstat) to check Server
Performance
• Determine which Resource(s) are being
over utilized
• Finding the bottleneck is key

Emergency Profiling
• What Changed?
• Increased Traffic?
• New Feature?
• Something Failed/Down?
• Don’t Panic & Start Wildly Guessing

Few Final Thoughts

The Better You
Understand
The Problem
The Better You Can
Fix It

Don’t
Put Off Profiling
Until there is an
Emergency

You Can Throw
Hardward at the
Problem, but Avoid IT

Ask Others for Ideas
aka
Brainstorming

Good Luck!

Questions?

Thanks!
Twitter: JustinCarmony
IRC: carmony
#uphpu #phpc #joind.in
Website:
http://www.justincarmony.com/blog
Email:
justin@justincarmony.com