1. High Performance
WordPress
WordCamp Jerusalem
September 5, 2010

2. About Me
Barry Abrahamson
Systems Wrangler, Automattic
http://barry.wordpress.com/contact-me/

3. WordPress.com

4. WordPress.com
Launched in August 2005

5. WordPress.com
Launched in August 2005
~13.5 million sites and 16 million users today

6. WordPress.com
Launched in August 2005
~13.5 million sites and 16 million users today
Over 2 billion HTTP requests per day

7. WordPress.com
Launched in August 2005
~13.5 million sites and 16 million users today
Over 2 billion HTTP requests per day
Billions of MySQL queries per month

8. WordPress.com
Launched in August 2005
~13.5 million sites and 16 million users today
Over 2 billion HTTP requests per day
Billions of MySQL queries per month
500TB of bandwidth per week

9. What is Performance?

10. What is Performance?
Speed - Serve each request as quickly as possible

11. What is Performance?
Speed - Serve each request as quickly as possible
Scaling - Serve many concurrent requests

12. Speed

13. Speed
Server

14. Speed
Server
Generating the content

15. Speed
Server
Generating the content
Client

16. Speed
Server
Generating the content
Client
Downloading

17. Speed
Server
Generating the content
Client
Downloading
Parsing

18. Speed
Server
Generating the content
Client
Downloading
Parsing
Displaying

19. Speed
Server
Generating the content
Client
Downloading
Parsing
Displaying

20. Client Side Performance

21. Client Side Performance
80%+ of the total load time

22. Client Side Performance
80%+ of the total load time
Tools

23. Client Side Performance
80%+ of the total load time
Tools
YSlow - http://developer.yahoo.com/yslow/

24. Client Side Performance
80%+ of the total load time
Tools
YSlow - http://developer.yahoo.com/yslow/
Page Speed - http://code.google.com/speed/
page-speed/

25. Client Side Performance

26. Client Side Performance
Reduce number of HTTP Requests

27. Client Side Performance
Reduce number of HTTP Requests
Compress (gzip)

28. Client Side Performance
Reduce number of HTTP Requests
Compress (gzip)
Optimize images (resize, pngcrush, jpegtran)

29. Server Side Performance

30. Server Side Performance
More important than client side performance

31. Server Side Performance
More important than client side performance
Tools aren’t as advanced / fancy as client tools

32. Server Side Performance

33. Server Side Performance
Possible problems

34. Server Side Performance
Possible problems
Slow database queries

35. Server Side Performance
Possible problems
Slow database queries
PHP (CPU)

36. Server Side Performance
Possible problems
Slow database queries
PHP (CPU)
Network

37. Server Side Performance
Possible problems
Slow database queries
PHP (CPU)
Network
Tools

38. Server Side Performance
Possible problems
Slow database queries
PHP (CPU)
Network
Tools
WordPress Plugins - Search for “debug”

39. WordPress.com Debug Tools

42. Server Side Performance

43. Server Side Performance
Tools

44. Server Side Performance
Tools
MySQL Slow query log

45. Server Side Performance
Tools
MySQL Slow query log
http://www.maatkit.org/doc/mk-query-digest.html

46. Server Side Performance
Tools
MySQL Slow query log
http://www.maatkit.org/doc/mk-query-digest.html
Strace / lsof / gdb

47. Server Side Performance
Tools
MySQL Slow query log
http://www.maatkit.org/doc/mk-query-digest.html
Strace / lsof / gdb
Many times plugins are the culprit.

48. How can I improve
performance?

49. As a User

50. As a User
Make sure you are running the latest WordPress!

51. As a User
Make sure you are running the latest WordPress!
Constant performance improvements being made.
Many from things found on WordPress.com

52. As a User
Make sure you are running the latest WordPress!
Constant performance improvements being made.
Many from things found on WordPress.com
Show a reasonable number of posts per page. 10-25
seems to be good

53. As a User
Make sure you are running the latest WordPress!
Constant performance improvements being made.
Many from things found on WordPress.com
Show a reasonable number of posts per page. 10-25
seems to be good
Monitor site performance

54. As a Sysadmin

55. As a Sysadmin
Opcode cache (APC)

56. As a Sysadmin
Opcode cache (APC)
Caching plugins (Batcache, WP super cache)

57. As a Sysadmin
Opcode cache (APC)
Caching plugins (Batcache, WP super cache)
Make sure you are running the latest PHP

58. As a Sysadmin
Opcode cache (APC)
Caching plugins (Batcache, WP super cache)
Make sure you are running the latest PHP
HipHop

59. As a Sysadmin
Opcode cache (APC)
Caching plugins (Batcache, WP super cache)
Make sure you are running the latest PHP
HipHop
Apache + mod_php < Nginx + php-fpm.

60. Real World Numbers

61. Real World Numbers
APC

62. Real World Numbers
APC
Empty cache - 33.5 MB RAM

63. Real World Numbers
APC
Empty cache - 33.5 MB RAM
Primed cache - 6.2 MB RAM

64. Real World Numbers
APC
Empty cache - 33.5 MB RAM
Primed cache - 6.2 MB RAM
60% reduction in CPU utilization ( 2160 CPUs )

65. Real World Numbers
APC
Empty cache - 33.5 MB RAM
Primed cache - 6.2 MB RAM
60% reduction in CPU utilization ( 2160 CPUs )
PHP 5.3.3 10% CPU reduction ( 360 CPUs )

66. Real World Numbers

67. Real World Numbers
HipHop

68. Real World Numbers
HipHop
40% faster ( http://huichen.org/en/2010/06/
wordpress-3-benchmark/ )

69. Real World Numbers
HipHop
40% faster ( http://huichen.org/en/2010/06/
wordpress-3-benchmark/ )
270% faster ( http://huichen.org/en/2010/06/
wordpress-3-benchmark-part-2/ )

70. Real World Numbers

71. Apache + mod_php
1 request requiring php
Using mod_php, php is
loaded for every request
even if not needed
Most scaling problems are
because of this

72. As a Developer

73. As a Developer
Only perform write operations when needed. Example
is flushing rewrite rules on every page load

74. As a Developer
Only perform write operations when needed. Example
is flushing rewrite rules on every page load
Use WordPress functions when possible.

75. WordPress.com

76. WordPress.com
~ 1100 servers in 3 datacenters
~ 450 web servers (8 CPU cores)
~ 400 database servers (lots of SSDs)
~ 75 memcached servers (800GB of RAM)

77. Scaling Tips

78. Scaling Tips
Most things you do to scale WordPress apply to
any web app

79. Scaling Tips
Most things you do to scale WordPress apply to
any web app
If your bottleneck is the database, something is
wrong

80. Scaling Tips
Most things you do to scale WordPress apply to
any web app
If your bottleneck is the database, something is
wrong
Measure twice, cut once, measure again

81. Scaling Tips
Most things you do to scale WordPress apply to
any web app
If your bottleneck is the database, something is
wrong
Measure twice, cut once, measure again
Don’t optimize if you don’t need to

82. Questions?