1. CACHING FOR CASH -
BENCHMARKING
Scott MacVicar + Helgi Þormar Þorbjörnsson
php|works 2008

2. GOALS
Learn how to find slow pages
Locate slow blocks of code
Apply minor optimisations

3. THOUGHT STEPS
Things seem a bit slow
Take a guess whats slow
Browse lots of code

4. SYSTEM COMPONENTS
Appliation Server
Database Server
Application
Database
Network

5. PAGE BENCHMARKING
Single Request doesn’t matter
Average time for maximum amount of users
Hopefully at worst it scales linearly

6. REQUIREMENTS
Same hardware configuration
Same server configuration
Same network interface speed (100mbps)
Basically your “staging server”

7. STEPS TO BENCHMARK
Record server load
Run our tests at least 3 times
Take average of tests

8. BENCHMARKING TOOLS
Apache Bench
Apache Flood
Siege

9. APACHE BENCH
Shows requests per
second
Bundled with Apache
Gives relative idea of
load

10. APACHE BENCH - DEMO
1000 Requests with 5 at a time
ab -n 1000 -c 5 http://localhost/phpBB3/index.php
1000 requests with 5 at a time using keep alive
ab -n 1000 -c 5 -k http://localhost/phpBB3/index.php
Output results to Excel / GNUPlot
ab -n 1000 -c 5 -g http://localhost/phpBB3/index.php

11. ISSUES WITH APACHE BENCH
Synthetic Benchmark
No way to emulate users

12. APACHE FLOOD
Profile driven
benchmarking
XML Based config
Use variables on pages

13. XML FORMAT
URLLIST
FARM
FARMER
PROFILE

14. URLIST
Simple group of URLs
Supports postdelay and predelay

15. FARMER
Single User
Can use URLLIST in various ways
Random Order
Round Robin
Keep-Alive

16. FARM
It’s where the farmers work
Controls the way the farmers work
Creates farmers too

17. PROFILE
Runtime configuration
Can change various settings
socket
report

18. USE CASES
User visits main page
User visits main page then download page
User visits main page then download and downloads
a file

19. SINGLE PAGE
Keep Alive
Page Image Image

20. SINGLE PAGE XML

21. TWO PAGE VISITS
Keep Alive
Page Image Image
30 secs
later
Keep Alive
Page Image Image

22. TWO PAGE VISITS XML

23. TWO PAGE VISITS AND
DOWNOAD
Keep Alive
Page Image Image
30 secs
later
Keep Alive
Page Image Image
15 secs
later
ISO

24. TWO PAGE VISIT AND
DOWNOAD XML

25. SETUP A PROFILE
enable keepalive
use the relative times output format
check for 200 OK

26. PROFILE XML

27. JOE THE FARMER

28. FARM FOR JOE TO WORK ON

29. RUNNING FLOOD
flood <configuration.xml> > output.file
anaylze-relative output.file

30. VMWARE INSTALL
Run
Run VMware- VMware-
Run VMWare-fusion.dmg
player-2.5.0-118166.exe Player-2.5.0-118166.i386
.bundle
Reboot
Copy Fedora 10 Folder to Disk
Load via VMWare
php / password

31. TASK
• Visit http://localhost/phpBB3/
• View a forum after 20 seconds
• View a thread after 5 seconds
• Click reply after 60 seconds
• Sample file in flood-examples folder

32. SIEGE
Provides functionality of Apache Bench and Flood
Supports GET and POST with a simple syntax
Benchmark and Internet mode

33. SIEGE COMMANDS
1000 Requests with 5 at a time
siege -b -r 1000 -c 5 http://localhost/phpBB3/index.php
10 seconds with concurrency of 5
siege -b -c 5 -t 10 http://localhost/phpBB3/index.php
Read urls.txt for a list of URLs
siege -b -n 1000 -c 5

34. SPROXY
Creates local socks proxy on your machine
Set your browser to use the local proxy, port 9001
Browse your site with the actions you wish
urls.txt is written with the POST and GET data

35. OTHER BENCHMARKING
TOOLS
JMeter
httperf
Web Application Stress Tool
OpenWebLoad

36. PROFILING

37. WHAT IS PROFILING
Examines the performance characteristics
Records every function call
Tracks execution time
Tracks memory usage

38. PROFILING TOOLS
XDebug
apd

39. XDEBUG
Debugger
Code Coverage
Memory and Executon time

40. XDEBUG PROTECTIONS
Stack overflow in PHP
Infinite Recursion

42. ERROR MESSAGE HELPING

43. XDEBUG HELPFUL ERROR
MESSAGES

44. MORE ERROR MESSAGE
HELPING

45. EXECUTION TIME

46. MEMORY USAGE

47. EXECUTION TRACE
xdebug.auto_trace=1
xdebug.trace_output_dir=/tmp
xdebug.collect_params=1
xdebug.collect_return=1
xdebug.trace_output_name=trace.%c

48. EXECUTION TRACE

49. PARTIAL EXECUTION TRACE
Tracing only parts of an application with
xdebug_start_trace() and xdebug_stop_trace().
Fetching the trace file name that is being used with
xdebug_get_tracefile_name().
Changing how much data is shown with
xdebug.var_display_max_children,
xdebug.var_display_max_data and
xdebug.var_display_max_depth.

50. CODE COVERAGE
Finds unexecuted code
xdebug_start_code_coverage()
xdebug_get_code_coverage()
xdebug_stop_code_coverage()

51. CODE COVERAGE SAMPLE

52. CODE COVERAGE OUTPUT

53. PROFILING
Execute action as normal in browser
Outputs cachegrind file
INI settings:
xdebug.profiler_enable=1 ; enable profiler
xdebug.profile_output_dir=/tmp ; output directory
xdebug.profile_output_name=cachegrind.out.%p

54. PROFILING CONTINUED
Locate parts of the code that is slow
Work down tree to find the slow sections
Can it be cached? Can it be optimized?
Occasionally built?

55. VIEWING PROFILE
KCacheGrind
MacCallGrind
WinCacheGrind
Carica CacheGrind

56. PROFILING DEMO

57. TASK
sudo nano -w /etc/php.d/xdebug.ini
remove ; from xdebug.profiler_enabled=1
Profile a page on Wordpress
Profile a page on phpBB
Try to find something slow you think could be
improved
20 minutes

58. APD
Lives in PECL
Similar to XDebug
Doesn’t require KCachegrind
Still only PHP 4

59. APD
apd_set_pprof_trace() to enable profiler
pprof is a script to interpret the trace
Outputs to apd.dumpdir

60. BRINGING IT TOGETHER
Use profiler with benchmarks
Profiling can be run on production sites
Optimise slow code

61. RESOURCES
Lunch - back at 1pm for Caching
http://talks.macvicar.net/
http://httpd.apache.org/test/flood/
http://xdebug.org/docs/
http://www.joedog.org