1. Lorenzo Alberton
Profile your PHP application
and make it fly
The path to performance
and scalability
PHPNW, Saturday 9th October 2010
1

2. Quiz time!
Which is faster?
2

3. Quiz time!
Which is faster?
(A) echo (B) print
2

4. Quiz time!
Which is faster?
(A) echo
single (B) print
double
quotes quotes
2

5. Answer
It probably doesn’t matter.
3

6. Awareness is the
Know your targets
Know what it will take to meet them
Know your constraints
4

7. Tools: Profilers
Tools are just tools
They are absolutely essential
to doing your job
They will never do your job for you
Tools will never replace
experience and discipline
But tools can help you
maintain discipline
Theo Schlossnagle
5

8. Xdebug + xCacheGrind
http://xdebug.org/
http://valgrind.org/
http://kcachegrind.sf.net/
http://sf.net/projects/wincachegrind
http://code.google.com/p/webgrind/
http://www.maccallgrind.com/
6

9. XHProf
XHProf
http://mirror.facebook.net/facebook/xhprof/
http://pecl.php.net/package/xhprof
http://techportal.ibuildings.com/2009/12/01/profiling-with-xhprof/
7

10. XHProf UI Report - Web interface
8

11. XHProf UI Report - Web interface
8

12. XHProf UI Report - Web interface
8

13. XHProf UI Report - Web interface
Function Name
Calls
Wall Time (inclusive / exclusive)
CPU (inclusive / exclusive)
Memory (inclusive / exclusive)
Peak Memory Use (inclusive / exclusive)
# and %
8

14. XHProf UI - Trace calls
9

15. XHProf UI - Call Graph
10

16. XHProf UI - Call Graph
10

17. Measuring
Analyse the framework
Analyse your application
11

18. Know Your Framework
Measure the baseline
Shortcuts aren’t always “free”
When there are two ways of doing something,
usually one is much better
Loading (classes, resources) is expensive
12

19. Zend Framework Baseline
$ zf.sh create project testzf
13

20. Know Your Framework
Measure the baseline
Shortcuts aren’t always “free”
When there are two ways of doing something,
usually one is much better
Loading (classes, resources) is expensive
14

21. Shortcuts - The Real Cost
public function doSomething(array $data) {
// Zend_Config object
$config = $this->getConfig();
$var = $config->aaa->bbb->ccc;
// ...
}
15

22. Shortcuts - The Real Cost
public function doSomething(array $data) {
// Zend_Config object
$config = $this->getConfig();
$var = $config->aaa->bbb->ccc;
// ...
}
15

23. Shortcuts - The Real Cost
public function doSomething(array $data) {
// Zend_Config object
$config = $this->getConfig();
$var = $config->aaa->bbb->ccc;
// ...
}
15

24. Shortcuts - The Real Cost
public function doSomething(array $data) {
// Zend_Config object
$config = $this->getConfig();
$var = $config->aaa->bbb->ccc;
// ...
}
2
1
3
15

25. Know Your Framework
Measure the baseline
Shortcuts aren’t always “free”
When there are two ways of doing something,
usually one is much better
Loading (classes, resources) is expensive
16

26. partial() vs. render()
<!-- mytemplate.phtml -->
<ul>
<?php
foreach ($this->rows as $row) {
$this->partial(‘listItemTemplate.phtml’,
‘mymodule’, array(‘data’ => $row);
}
?>
</ul>
17

27. partial() vs. render()
18

28. partial() vs. render()
18

29. partial() vs. render()
18

30. partial() vs. render()
18

31. partial() vs. render()
18

32. partial() vs. render()
18

33. partial() vs. render()
18

34. partial() vs. render()
<!-- mytemplate.phtml -->
<ul>
<?php
foreach ($this->rows as $row) {
$this->partial(‘listItemTemplate.phtml’,
‘mymodule’, array(‘data’ => $row);
}
?>
</ul>
19

35. partial() vs. render()
<!-- mytemplate.phtml -->
<ul>
<?php
foreach ($this->rows as $row) {
$this->row) {
$this->render(‘listItemTemplate.phtml’);
$this->partial(‘listItemTemplate.phtml’,
} ‘mymodule’, array(‘data’ => $row);
?>
}
</ul>
?>
</ul>
19

36. Know Your Framework
Measure the baseline
Shortcuts aren’t always “free”
When there are two ways of doing something,
usually one is much better
Loading (classes, resources) is expensive
20

37. Plugins / Helpers
<!-- mytemplate.phtml -->
<ul>
<?php
foreach ($this->rows as $row) {
echo $this->myViewHelper($row);
}
?>
</ul>
21

38. Plugins / Helpers
// calling:
// Zend_View_Abstract::__call()
<!-- mytemplate.phtml -->
// Zend_View_Abstract::getHelper()
<ul>
// Zend_View_Abstract::_getPlugin()
<?php
// Zend_View_Abstract::_getPluginLoader()
// Zend_Loader_PluginLoader::load()
foreach ($this->rows as $row) {
// Zend_Loader_PluginLoader::isLoaded()
echo $this->myViewHelper($row);
// Zend_Loader_PluginLoader::getClassName()
}
// Zend_Loader_PluginLoader::_formatName()
// Zend_View_Abstract::setView()
?>
// call_user_func_array()
</ul>
// My_Helpers_MyViewHelper::myViewHelper()
21

39. Plugins / Helpers
<!-- mytemplate.phtml -->
<ul>
<?php
foreach ($this->rows as $row) {
echo $this->myViewHelper($row);
}
?>
</ul>
21

40. Plugins / Helpers
<!-- mytemplate.phtml -->
<ul>
<?php
foreach
$helper = $this->getHelper('myViewHelper');
($this->rows as $row) {
echo $this->myViewHelper($row);
foreach
} ($this->rows as $row) {
echo $helper->myViewHelper($row);
}
?>
</ul>
?>
</ul>
21

41. Know Your Application
Every feature has a cost. Measure it.
22

42. Optimisation Techniques
Tips and tricks to get faster applications
23

43. Rules of thumb
Profile / Measure
Sort by [ Excl. CPU | Memory | Time | Calls ]
Start from the TOP of the list
Analyse, refactor, optimise
Measure improvement
Start over
24

44. Rules of thumb
Profile / Measure
Sort by [ Excl. CPU | Memory | Time | Calls ]
Start from the TOP of the list
Analyse, refactor, optimise
Measure improvement
Start over
Again, and again, and again.
24

45. Profiling as Design validation practice
25

46. Easy performance targets
External resources (http, db, disk I/O)
Memory-hungry function
(xml/json parsers, output buffering)
Loops
Regular expressions
Wrappers
26

47. Refactoring hints
PREPARE SCREEN
showing db calls
27

48. Refactoring hints
PREPARE SCREEN
showing db calls
27

49. Refactoring hints
28

50. Refactoring hints
28

51. Refactoring hints
28

52. Refactoring hints
29

53. Refactoring hints
PHP is FAST
29

54. Refactoring hints
PHP is FAST
...but do you really need to call strtolower()
15000 times?
29

55. Refactoring hints
PHP is FAST
...but do you really need to call strtolower()
15000 times?
Re-think why you’re doing something,
if it’s the right place to do it,
and if possible reduce the amount of data you
need to process
29

56. Code smells
Immutable functions called within loops
Same content being generated twice
Content that does not change being generated every time
Content being generated even if not used
30

57. Code smells
Immutable functions called within loops
Same content being generated twice
Content that does not change being generated every time
Content being generated even if not used
Sometimes it’s less obvious than it might seem
30

58. Caching (computational reuse)
Static variables
APC / Zend Server Cache / ...
Memcached
Reverse proxies
Browser
31

59. Caching (computational reuse)
Static variables
APC / Zend Server Cache / ...
Memcached
Reverse proxies
Browser
Do no work at all, if you can avoid it
31

60. [Cache] Layers!
32

61. System calls
strace / ltrace / dtrace / ktrace / truss
# httpd -X &
[1] 5772
# strace -p 5772 -o /tmp/strace.out
Process 5772 attached - interrupt to quit
# curl http://mysite.local/
# less /tmp/strace.out
33

62. System calls
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
strace / ltrace / dtrace / ktrace / truss
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
lstat("/mnt/hgfs/service_layer", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches", {st_mode=S_IFDIR|0755, st_size=102, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9", {st_mode=S_IFDIR|0755, st_size=238, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/library", {st_mode=S_IFDIR|0755, st_size=136, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/library/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
open("/mnt/hgfs/service_layer/branches/1.9/php/library/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
lstat("/mnt/hgfs/service_layer", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches", {st_mode=S_IFDIR|0755, st_size=102, ...}) = 0
# httpd -X &
lstat("/mnt/hgfs/service_layer/branches/1.9", {st_mode=S_IFDIR|0755, st_size=238, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/application", {st_mode=S_IFDIR|0755, st_size=340, ...}) = 0
[1] 5772
lstat("/mnt/hgfs/service_layer/branches/1.9/php/application/models", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/application/models/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
open("/mnt/hgfs/service_layer/branches/1.9/php/application/models/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
getcwd("/mnt/hgfs/service_layer/branches/1.9/php/public"..., 4096) = 48
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
lstat("/mnt/hgfs/service_layer", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
# strace -p 5772 -o /tmp/strace.out
lstat("/mnt/hgfs/service_layer/branches", {st_mode=S_IFDIR|0755, st_size=102, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9", {st_mode=S_IFDIR|0755, st_size=238, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
Process 5772 attached - interrupt to quit
lstat("/mnt/hgfs/service_layer/branches/1.9/php/public", {st_mode=S_IFDIR|0755, st_size=340, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/public/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
open("/mnt/hgfs/service_layer/branches/1.9/php/public/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
lstat("/var", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/var/www", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/var/www/commonlib", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/var/www/commonlib/current", {st_mode=S_IFLNK|0777, st_size=32, ...}) = 0
readlink("/var/www/commonlib/current", "/mnt/hgfs/commonlib/branches/1.9"..., 4096) = 32
# curl http://mysite.local/
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
lstat("/mnt/hgfs/commonlib", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
lstat("/mnt/hgfs/commonlib/branches", {st_mode=S_IFDIR|0755, st_size=136, ...}) = 0
lstat("/mnt/hgfs/commonlib/branches/1.9", {st_mode=S_IFDIR|0755, st_size=272, ...}) = 0
lstat("/mnt/hgfs/commonlib/branches/1.9/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
open("/var/www/commonlib/current/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
# less /tmp/strace.out
lstat("/usr/local", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend/Controller", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend/Controller/Plugin", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend/Controller/Plugin/Abstract.php", {st_mode=S_IFREG|0644, st_size=4298, ...}) = 0
open("/usr/local/zend/share/ZendFramework/library/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = 40
33

63. System calls
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
strace / ltrace / dtrace / ktrace / truss
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
lstat("/mnt/hgfs/service_layer", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches", {st_mode=S_IFDIR|0755, st_size=102, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9", {st_mode=S_IFDIR|0755, st_size=238, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/library", {st_mode=S_IFDIR|0755, st_size=136, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/library/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
open("/mnt/hgfs/service_layer/branches/1.9/php/library/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
...
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
lstat("/mnt/hgfs/service_layer", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
getcwd("/var/www/site/php/public"..., 4096) = 48
lstat("/mnt/hgfs/service_layer/branches", {st_mode=S_IFDIR|0755, st_size=102, ...}) = 0
# httpd -X &
lstat("/mnt/hgfs/service_layer/branches/1.9", {st_mode=S_IFDIR|0755, st_size=238, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
lstat("/var", {st_mode=S_IFDIR|0755, st_size=4096}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/application", {st_mode=S_IFDIR|0755, st_size=340, ...}) = 0
[1] 5772
lstat("/mnt/hgfs/service_layer/branches/1.9/php/application/models", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/application/models/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
lstat("/var/www", {st_mode=S_IFDIR|0555, st_size=4192}) = 0
open("/mnt/hgfs/service_layer/branches/1.9/php/application/models/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
getcwd("/mnt/hgfs/service_layer/branches/1.9/php/public"..., 4096) = 48
lstat("/var/www/site", {st_mode=S_IFDIR|0755, st_size=170}) = 0
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
lstat("/mnt/hgfs/service_layer", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
lstat("/var/www/site/php", -o /tmp/strace.out
# strace -p 5772 {st_mode=S_IFDIR|0755, st_size=306}) = 0
lstat("/mnt/hgfs/service_layer/branches", {st_mode=S_IFDIR|0755, st_size=102, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9", {st_mode=S_IFDIR|0755, st_size=238, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php", {st_mode=S_IFDIR|0755, st_size=306, ...}) = 0
lstat("/var/www/site/php/public", {st_mode=S_IFDIR|0755, st_size=340}) = 0
Process 5772 attached - interrupt to quit
lstat("/mnt/hgfs/service_layer/branches/1.9/php/public", {st_mode=S_IFDIR|0755, st_size=340, ...}) = 0
lstat("/mnt/hgfs/service_layer/branches/1.9/php/public/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
lstat("/var/www/site/php/public/Zend", 0x7fff89049af0) = -1 ENOENT
open("/mnt/hgfs/service_layer/branches/1.9/php/public/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
lstat("/var", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/var/www", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
(No such file or directory)
lstat("/var/www/commonlib", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/var/www/commonlib/current", {st_mode=S_IFLNK|0777, st_size=32, ...}) = 0
readlink("/var/www/commonlib/current", "/mnt/hgfs/commonlib/branches/1.9"..., 4096) = 32
open("/var/www/site/php/public/Zend/Controller/Plugin/Abstract.php",
# curl http://mysite.local/
lstat("/mnt", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/mnt/hgfs", {st_mode=S_IFDIR|0555, st_size=4192, ...}) = 0
O_RDONLY) = -1 ENOENT (No such file or directory)
lstat("/mnt/hgfs/commonlib", {st_mode=S_IFDIR|0755, st_size=170, ...}) = 0
lstat("/mnt/hgfs/commonlib/branches", {st_mode=S_IFDIR|0755, st_size=136, ...}) = 0
lstat("/mnt/hgfs/commonlib/branches/1.9", {st_mode=S_IFDIR|0755, st_size=272, ...}) = 0
lstat("/mnt/hgfs/commonlib/branches/1.9/Zend", 0x7fff89049af0) = -1 ENOENT (No such file or directory)
...
open("/var/www/commonlib/current/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = -1 ENOENT (No such file or directory)
lstat("/usr", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
# less /tmp/strace.out
lstat("/usr/local", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend/Controller", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend/Controller/Plugin", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/local/zend/share/ZendFramework/library/Zend/Controller/Plugin/Abstract.php", {st_mode=S_IFREG|0644, st_size=4298, ...}) = 0
open("/usr/local/zend/share/ZendFramework/library/Zend/Controller/Plugin/Abstract.php", O_RDONLY) = 40
33

64. System calls
# grep 'stat' /tmp/strace.out | wc -l
20511
# /usr/bin/strace -p 5772 -c
Process 5772 attached - interrupt to quit
Process 5772 detached
% time seconds usecs/call calls errors syscall
------ ---------- ---------- ------ ------ -------
50.86 0.131501 7 20054 2029 lstat
28.42 0.073497 742 99 76 access
16.78 0.043385 32 1337 1095 open
1.61 0.004167 5 798 1 read
0.94 0.002436 13 193 getcwd
...
------ ---------- ---------- ------ ------ -------
100.00 0.020951 1267 103 total
34

65. System calls
# grep 'stat' /tmp/strace.out | wc -l
20511
# /usr/bin/strace -p 5772 -c
Process 5772 attached - interrupt to quit
Process 5772 detached
% time seconds usecs/call calls errors syscall
------ ---------- ---------- ------ ------ -------
50.86 0.131501 7 20054 2029 lstat
28.42 0.073497 742 99 76 access
16.78 0.043385 32 1337 1095 open
1.61 0.004167 5 798 1 read
0.94 0.002436 13 193 getcwd
...
------ ---------- ---------- ------ ------ -------
100.00 0.020951 1267 103 total
34

66. Fix include_path (disk I/O)
set_include_path(implode(PATH_SEPARATOR, array(
‘../library/’, // project library classes
‘./models/’, // project models
‘/usr/local/php/share/’, // framework
));
The order (and number!) of
the include paths is important.
Tip: increase the realpath_cache size.
35

67. Fix include_path (disk I/O)
set_include_path(implode(PATH_SEPARATOR, array(
‘../library/’, // project// framework
‘/usr/local/php/share/’, library classes
‘./models/’,
‘../library/’, // project models classes
library
‘/usr/local/php/share/’, // framework
‘./models/’, // project models
));
The order (and number!) of
the include paths is important.
Tip: increase the realpath_cache size.
35

68. Apache config
open("/var/www/.htaccess", O_RDONLY) = -1 ENOENT
open("/var/www/php/.htaccess", O_RDONLY) = -1 ENOENT
open("/var/www/php/site/.htaccess", O_RDONLY) = -1 ENOENT
open("/var/www/php/site/org/.htaccess", O_RDONLY) = -1 ENOENT
open("/var/www/php/site/org/view/.htaccess", O_RDONLY) = -1 ENOENT
...
open("/var/www/php/site/index.html", O_RDONLY) = -1 ENOENT
open("/var/www/php/site/index.cgi", O_RDONLY) = -1 ENOENT
open("/var/www/php/site/index.php", O_RDONLY) = 0
...
open("/var/www/php/site/favicon.ico", O_RDONLY) = -1 ENOENT
Turn AllowOverride off
Optimise DirectoryIndex
Add favicon.cio
36

69. Fix autoloader (disk I/O)
function __autoload($className) {
if (class_exists($className, false)) return;
if ( (($file = apc_fetch($className)) === false)
|| ($file === null)) {
$classFile = str_replace(‘_’,
DIRECTORY_SEPARATOR, $className) . ‘.php’;
$file = stream_resolve_include_path($classFile);
if ($file !== false) {
apc_store($className, $file, 86400);
} else {
apc_store($className, null, 86400);
}
}
if (($file !== false) && ($file !== null)) {
include $file;
}
}
37

70. Fix autoloader (disk I/O)
function __autoload($className) {
if (class_exists($className, false)) return;
if ( (($file = apc_fetch($className)) === false)
|| ($file === null)) {
$classFile = str_replace(‘_’,
DIRECTORY_SEPARATOR, $className) . ‘.php’;
$file = stream_resolve_include_path($classFile);
if ($file !== false) {
apc_store($className, $file, 86400);
} else {
apc_store($className, null, 86400);
}
}
if (($file !== false) && ($file !== null)) {
include $file;
}
}
37

71. Fix autoloader (disk I/O)
function __autoload($className) {
if (class_exists($className, false)) return;
if ( (($file = apc_fetch($className)) === false)
|| ($file === null)) {
$classFile = str_replace(‘_’,
DIRECTORY_SEPARATOR, $className) . ‘.php’;
$file = stream_resolve_include_path($classFile);
if ($file !== false) {
apc_store($className, $file, 86400);
} else {
apc_store($className, null, 86400);
}
}
if (($file !== false) the ($file !== null)) {
Rely on && autoloader.
include $file;
} Avoid explicit includes
} http://devzone.zend.com/article/4525
37

72. OPCode cache
APC XCache
Zend Accelerator WinCache
eAccelerator ...
38

73. OPCode cache
APC XCache
Zend Accelerator WinCache
eAccelerator ...
# grep 'open(' /tmp/strace.out
open("/usr/local/php/share/Zend/Log.php", O_RDONLY) = 40
open("/usr/local/php/share/Zend/Form.php", O_RDONLY) = 40
open("/usr/local/php/share/Zend/Locale.php", O_RDONLY) = 40
38

74. OPCode cache
APC XCache
Zend Accelerator WinCache
eAccelerator ...
# grep 'open(' /tmp/strace.out
open("/usr/local/php/share/Zend/Log.php", O_RDONLY) = 40
open("/usr/local/php/share/Zend/Form.php", O_RDONLY) = 40
open("/usr/local/php/share/Zend/Locale.php", O_RDONLY) = 40
Conditional includes may cause
OPCode cache trashing
38

75. Include Hierarchy - PECL inclued
http://pecl.php.net/package/inclued
39

76. Watch your error log!
Warning: Undefined index: NAME in file.php on line 1269
Warning: Undefined index: DESC in file.php on line 1270
Warning: Undefined variable: $str in a.php on line 341
Warning: Undefined index: DESC in file.php on line 1270
@
Error suppression is bad
http://derickrethans.nl/five-reasons-why-the-shutop-operator-should-be-avoided.html
40

77. Watch your error log!
Warning: Undefined index: NAME in file.php on line 1269
Warning: Undefined index: DESC in file.php on line 1270
Warning: Undefined variable: $str in a.php on line 341
Warning: Undefined index: DESC in file.php on line 1270
@
Error suppression is bad
http://derickrethans.nl/five-reasons-why-the-shutop-operator-should-be-avoided.html
40

78. Log and analyse external requests
/* HTTP Client */
function request($url, $method = ‘GET’) {
$this->log(‘[HTTP] ’ . $method . ‘ ’ . $url);
$ch = curl_init();
// ...
}
/* DB Client */
function query($sql) {
$this->log(‘[DB] ’ . $query);
// ...
return $this->db->query($sql);
}
41

79. Log and analyse external requests
/* HTTP Client */
function request($url, $method = ‘GET’) {
$this->log(‘[HTTP] ’ . $method . ‘ ’ . $url);
$ch = curl_init();
// ...
}
/* DB Client */
function query($sql) {
$this->log(‘[DB] ’ . $query);
// ...
return $this->db->query($sql);
}
41

80. Analyse logs (Observability)
[HTTP] GET http://myservice.com/list/somelist
[HTTP] GET http://myservice.com/id/1
[HTTP] PUT http://myservice.com/id/3/value/xyz
[HTTP] GET http://myservice.com/list/somelist
[HTTP] GET http://myservice.com/list/somelist
[DB] SELECT * FROM mytable;
[DB] SELECT name FROM cities ORDER BY name;
[DB] SELECT name FROM cities ORDER BY name;
[DB] SELECT name FROM cities ORDER BY name;
[DB] UPDATE mytable SET name=‘xyz’ WHERE id=3;
Consider caching frequent requests
42

81. Profile under load
Collect profile data from a sample of random requests
if (0 == mt_rand(0, 1000)) {
// collect profile data
}
43

82. Profile under load
Collect profile data from a sample of random requests
if (0 == mt_rand(0, 1000)) {
// collect profile data
}
Monitor resource usage in real time (top / htop / vmstat)
43

83. Profile under load
Collect profile data from a sample of random requests
if (0 == mt_rand(0, 1000)) {
// collect profile data
}
Monitor resource usage in real time (top / htop / vmstat)
Analyse graphs
JMeter
The Grinder
43

84. Performance Counters
Used / available memory (local, shared)
Pages / sec
Response time & Time-outs
Successful / failed transactions
Open sockets / connections
Bandwidth (internal network too!)
CPU
All the resources are limited
...
44

85. Thundering Herd
45

86. Circuit Breaker
46

87. Circuit Breaker
public function fetchData($key) {
return $this->callService($key);
}
47

88. Circuit Breaker
public function fetchData($key) {
$config = array(
'check_timeout' => 10,
'failure_threshold' => 10,
);
$cb = new Circuit_Breaker('name', $config);
if ($cb->isClosed()) {
$ok = $this->callService($key);
public function fetchData($key) {
if ($ok) {
return $this->callService($key);
} $cb->success();
} else {
//increment failures count
$cb->fail();
}
}
}
47

89. Poor man’s circuit breaker
public function fetchData($key) {
static $failures = 0;
if ($failures < self::MAX_FAILURES) {
$ok = $this->callService($key);
if ($ok) {
--$failures;
} else {
++$failures;
}
}
}
Save the counter in memcached
instead of a static variable, if possible
48

90. Reverse Proxy
http://www.varnish-cache.org/
49

91. Conclusions
Parting thoughts
50

92. Performance Checklist
Deep understanding of the problem at hand
Good architecture / design / data structures / algorithms
Do the absolute minimum
Use the right tools, always validate assumptions
Monitor resource usage (!), with many metrics
Spread the load uniformly across the resources
Decouple services
Good caching strategy strategies (sharing / reuse)
51

93. Links + References
http://www.slideshare.net/postwait/scalable-internet-architecture
http://techportal.ibuildings.com/2009/12/01/profiling-with-xhprof/
http://www.chehodgins.com/php/sorting-out-your-php-includes-using-inclued/
http://weierophinney.net/matthew/archives/245-Autoloading-Benchmarks.html
http://www.mail-archive.com/internals@lists.php.net/msg37192.html
http://talks.php.net/show/digg
http://mirror.facebook.net/facebook/xhprof/
http://xdebug.org/
http://github.com/facebook/pfff/
52

94. Image Credits
http://michaelscomments.files.wordpress.com/2009/10/onion-
centurion.jpg
http://www.socketmanufacturers.com/miniature-circuit-
breaker/DZ47-63-3P-Miniature-Circuit-Breaker.jpg
http://onscreencars.com/tv/the-homer-the-car-built-for-homer/
http://etc.usf.edu/presentations/themes/index.html
http://www.iconfinder.com/
53

95. Questions?
54

96. Lorenzo Alberton
@lorenzoalberton
Thank you!
lorenzo@alberton.info
http://www.alberton.info/talks
http://joind.in/talk/view/2051
55