PHP 7 Performance

Question

I've tried to reproduce this benchmark which compares PHP 7 with older versions on a Wordpress server: http://talks.php.net/oz15#/wpbench

My configuration is nearly the same, the server has an i7, SSD, 16GB RAM and debian. The server software is nginx. Suprisingly my results differ a lot from the ones linked above.

In my tests Siege (https://www.joedog.org/siege-home/) outputs the following:

For PHP 7.0.0RC1:

siege -c100 -r100 http://10.22.255.133/wordpress/
** SIEGE 3.0.8
** Preparing 100 concurrent users for battle.
The server is now under siege..      done.

Transactions:                  10000 hits
Availability:                  100.00 %
Elapsed time:                  131.61 secs
Data transferred:              95.77 MB
Response time:                 0.75 secs
Transaction rate:              75.98 trans/sec
Throughput:                    0.73 MB/sec
Concurrency:                   56.98
Successful transactions:       10000
Failed transactions:           0
Longest transaction:           1.01
Shortest transaction:          0.04

For PHP 5.6.12:

siege -c100 -r100 http://10.22.255.133/wordpress/
** SIEGE 3.0.8
** Preparing 100 concurrent users for battle.
The server is now under siege..      done.

Transactions:                  10000 hits
Availability:                  100.00 %
Elapsed time:                  63.41 secs
Data transferred:              95.77 MB
Response time:                 0.03 secs
Transaction rate:              157.70 trans/sec
Throughput:                    1.51 MB/sec
Concurrency:                   4.45
Successful transactions:       10000
Failed transactions:           0
Longest transaction:           0.63
Shortest transaction:          0.01

When looking at the transaction rate you can see, that PHP 5 is about two times faster than PHP 7. I can't believe that.

Another interesting fact is, that running this benchmark (http://www.php-benchmark-script.com/) results in PHP 7 being about 3 times faster than PHP 5 (of course on the same server where I've also tested Wordpress). The measured results were:

• PHP 7.0.0RC1 | PHP 5.5.28
• Math: 0.201 | 0.683
• String Manipulation: 0.271 | 0.77
• Loops: 0.166 | 0.486
• If Else: 0.12 | 0.295

I've uploaded both phpinfo() files in case that helps:

• PHP Version 7.0.0RC1: http://simsso.de/downloads/stackoverflow/php7.html
• PHP Version 5.6.12-0+deb8u1: http://simsso.de/downloads/stackoverflow/php5.html

Do you have any idea why PHP 7 is that much slower in my tests with Wordpress?

---

With opcache enabled PHP 7 is actually twice as fast as PHP 5. Thanks Mjh for your hint!

I've made the following measurements on a randomly filled WordPress Server.

Siege now outputs the following for PHP 7.0.0RC1:

Transactions:                  10000 hits
Availability:                 100.00 %
Elapsed time:                  62.14 secs
Data transferred:             604.20 MB
Response time:                  0.02 secs
Transaction rate:             160.93 trans/sec
Throughput:                     9.72 MB/sec
Concurrency:                    3.77
Successful transactions:       10000
Failed transactions:               0
Longest transaction:            0.41
Shortest transaction:           0.01 

And PHP 5.6.12:

siege -c100 -r100 http://10.22.255.133/wordpress/
** SIEGE 3.0.8
** Preparing 100 concurrent users for battle.
The server is now under siege..      done.

Transactions:                 10000 hits
Availability:                 100.00 %
Elapsed time:                 119.98 secs
Data transferred:             604.20 MB
Response time:                0.60 secs
Transaction rate:             83.35 trans/sec
Throughput:                   5.04 MB/sec
Concurrency:                  49.86
Successful transactions:      10000
Failed transactions:          0
Longest transaction:          4.06
Shortest transaction:         0.04

Answer 1

According to the output of phpinfo you posted, opcache isn't enabled for your PHP 7, while it is for PHP 5. That alone can amount for a huge difference.