Presentation of PHP application profiling and performance improvement

1. PHP Profiling/performance

2. PHP profiling/perfomance
Processing time,
Transmission time
CPU Bandwith
Memory
I/O

3. PHP profiling/perfomance
• Expected traffic
• Traffic growth
• Scalability means
• Evolutions to come…
Set the context
• Contextually : search engine, file generation,
task…
Establish the objectives

4. PHP profiling/perfomance
•Language
•Framework
•Libraries
•…
Adapt technologies

5. PHP profiling/perfomance
• Smart, structured code
• Lazy loading
• Static variables (singletons/registries)
• Cache
Code
• Autoloader
• Reduce and order include_path
• Client cache (HTTP headers Cache-Control, Expire)
• Avoid regexps
• …
Good practices
• Php.ini : realpath_cache_size
• Nginx : worker_processes, open_file_cache, multi_accept, keepalive, gzip
• Cache op-code
• Disable logs
Server configuration

6. PHP profiling/perfomance
• Ponctual inefficiencies/bottlenecks
detection
• Monitoring (analytics, alert tools)
• Take comparison points (before/after)
• Know when to stop
• Never rely on intuition!
Measure

7. PHP profiling/perfomance
Load tests
• ApacheBenchmark
• Siege
• Httperf
• …
Profiling
• Xdebug
• XHProf
• …
Measuring
tools

8. PHP profiling/perfomance
ApacheBenchmark
ab -n 50 -c 2 -v 1 -p 'post.txt' -T 'application/json'
-H 'Authorization: Bearer eyJ0eXAi.eyJpc3nYXJ.KznbYbc'
'http://api.gma.my/account/authenticate?alt=json&metadata
[foo]=Hello&metadata[bar]=World&metadata[random Val]=Ted'
> bench.txt
{
"application_key":"afaf770",
"email":"ndegardin@tribalnova.com",
"key":"ndegardin«
}
post.txt

9. PHP profiling/perfomance
…
Concurrency Level: 2
Time taken for tests: 25.704 seconds
Complete requests: 50
Failed requests: 44
(Connect: 0, Receive: 0, Length: 44, Exceptions: 0)
Write errors: 0
Non-2xx responses: 50
Total transferred: 2231974 bytes
Total POSTed: 28100
HTML transferred: 2220474 bytes
Requests per second: 1.95 [#/sec] (mean)
Time per request: 1028.176 [ms] (mean)
Time per request: 514.088 [ms] (mean, across all concurrent requests)
Transfer rate: 84.80 [Kbytes/sec] received
1.07 kb/s sent
85.86 kb/s total
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 0.1 0 0
Processing: 704 1014 154.5 990 1693
Waiting: 704 1014 154.5 990 1693
Total: 705 1015 154.5 990 1693
…
bench.txt

10. PHP profiling/perfomance
• PHP profiling extension
• Developed by Facebook
• The basic version stores traces
• I diddn’t succeed in using the bundled
PHP/HTML app…
• With XHPROF, the profiling is triggered by
calling xhprof_enable(), xhprof_disable()
• Cool solution : auto_append_file,
auto_prepend_file in php.ini
XHProf

11. PHP profiling/perfomance
• Website http://xhprof.io
• Sources https://github.com/gajus/xhprof.io
• Profiling stored in database
• php.ini
• auto_append_file=/var/www/xhprofio/inc/append.php
• auto_prepend_file=/var/www/xhprofio/inc/prepend.php
• Not my recommandation
XHProf.io

12. PHP profiling/perfomance
• Sources https://github.com/sepehr/xhprof
• Profiling stored in database (one table « details »)
• Very good profiler
• php.ini
• auto_prepend_file=/var/www/xhprof/external/header.php
• auto_append_file=/var/www/xhprof/external/footer.php
• In CGI :
• activation by cookie _profile=1
• or by adding the parameter _profile=1 to the URL (adds the cookie,
then redirects)
• In CLI :
• auto_prepend/auto_append in/etc/php5/cli/php.ini
• activation by « export XHPROF_PROFILE=1 »
XHGUI

13. PHP profiling/perfomance
• Activate profiling by vhost in Apache
• Activate profiling by using a nginx/PHP-FPM pool :
/etc/php5/fpm/pool.d/www.conf :
• Activate profiling by vhost in nginx/PHP-FPM, in a
location section
XHProf notes
fastcgi_param PHP_ADMIN_VALUE
"auto_prepend_file=/var/www/xhprof/external/header.phpnauto_append_file=/var/
www/xhprof/external/footer.php";
php_admin_value auto_prepend_file "/var/www/xhprof/external/header.php"
php_admin_value auto_append_file "/var/www/xhprof/external/footer.php"
php_admin_value[auto_prepend_file] = /var/www/xhprofio/inc/prepend.php"
php_admin_value[auto_appendfile] = /var/www/xhprofio/inc/append.php"

14. PHP profiling/perfomance
• Web site http://xdebug.org/
• Developed by Derik Rethans
• PHP extension, now generally bundled with PHP
• Features :
• Debugging functions (time, calls, scream)
• Maximum nesting protection
• Enhanced stacktraces
• Remote debugging
• Profiling
• Code coverage
Xdebug

15. PHP profiling/perfomance
Xdebug notes about debugging
zend_extension=/usr/lib/php5/20090626/xdebug.so
xdebug.remote_enable = 1
xdebug.remote_handler = "dbgp"
xdebug.remote_port = 9000
xdebug.remote_mode = req
xdebug.remote_host = 192.168.56.1
xdebug.profiler_enable = 1
xdebug.profiler_output_dir = /var/log/xdebug
xdebug.profiler_output_name =
cachegrind.out.%H_%s_%R.xt
php.ini

16. PHP profiling/perfomance
• Prevent nginx from sending a gateway timeout (504) :
in /etc/nginx/nginx.conf, add
• Remote debug events triggered externally by setting a
XDEBUG_SESSION cookie and, if needed, mapping
paths (client/server) in your IDE
• Remote debug CLI scripts by running export
XDEBUG_CONFIG="idekey=netbeans-xdebug"and
setting php.ini xdebug.remote_host
Xdebug notes about debugging
fastcgi_read_timeout 3000;
keepalive_timeout 3000;
keepalive_requests 3000;
client_header_timeout 3000;
client_body_timeout 3000;
nginx.conf

17. PHP profiling/perfomance
• The traces are stored as files
• It often weights about 2Mo (be careful when forgetting it)
• Using a fixed name (without timestamp) in php.ini
xdebug.profiler.output_name allows a run script to erase the
previous one
• No official Xdebug trace extension, I suggest
cachegrind.out.[…].xt
• Profilers :
• WinCacheGrind (Windows) : somewhat simple
• WebGrind (Web) : « For quick’n’dirty optimizations it does the
job »
• KCacheGrind (KDE) : the best one
• PHPStorm : not really useful
Xdebug notes about profiling

18. PHP profiling/perfomance
• To run it under Windows, use KDE4Win
(package system similar to Cygwin’s one),
it should be in the « kdesdk » package.
Not available on all mirrors.
• Install GraphViz to enable drawing some
charts (and add its /bin directory the the
PATH)
• Check the Call Graph view!
kCacheGrind

19. PHP profiling/perfomance
• About different times :
• The wall time includes I/O (network latency, database
accesses, waiting for an user input…)
• The including time includes the children call
• The CPU exclusion time (self time in KCacheGrind) is the
more relevant value
• Switch between display formats :
• Percentage is better for comparing values
• Time is better for assessing values
• Tweaking script parameters (input configuration, number
of entries processed in database, number of iterations…)
may allow to observe different phenomena
Notes about profiling

20. Nicolas Degardin
ndegardin@tribalnova.com
Merci !