We have been working hard to improve the performance of PHP7. Last month we noticed that GCC’s PGO can bring nearly 10% performance improvement on WordPress. This makes us very excited.
However, as the name says, PGO (Profile Guided Optimization, if you are interested, Google it), it needs to use some use cases to obtain feedback, which means that this optimization needs to be bound to a specific scenario.
Your optimization in one scenario may backfire in another scenario. It is not a universal optimization. So we cannot simply include these optimizations, nor can we directly publish PGO compiled PHP7.
Of course, we are trying to find some common optimizations from PGO, and then manually apply them to PHP7, but this obviously cannot achieve the effect that special optimization for a scene can achieve, so I decided to write this article Briefly introduce how to use PGO to compile PHP7, so that the PHP7 you compile can make your own independent application faster.
First of all, the first thing to decide is what scenario to use for Feedback GCC. We usually choose: In the scenario you want to optimize: the page with the most visits, the most time-consuming, and the heaviest resource consumption.
Take WordPress as an example, we choose the homepage of WordPress (because the homepage is often the most visited).
Let’s take my machine as an example:
<ol class="dp-c"><li class="alt"><span><span>Intel(R) Xeon(R) CPU X5687 @ 3.60GHz X 16(超线程), </span></span></li><li><span> </span></li><li class="alt"><span>48G Memory </span></li></ol>
php-fpm uses a fixed 32 workers, and opcache uses the default configuration (be sure to load opcache)
Taking wordpress 4.1 as the optimization scenario..
First, let’s test the current performance of WP in PHP7 (ab -n 10000 -c 100):
<ol class="dp-c"><li class="alt"><span><span>$ ab -n 10000 -c 100 http:</span><span class="comment">//inf-dev-maybach.weibo.com:8000/wordpress/</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>This is ApacheBench, Version 2.3 <<span class="vars">$Revision</span><span>: 655654 $> </span></span></li><li><span> </span></li><li class="alt"><span>Copyright 1996 Adam Twiss, Zeus Technology Ltd, http:<span class="comment">//www.zeustech.net/</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Licensed to The Apache Software Foundation, http:<span class="comment">//www.apache.org/</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Benchmarking inf-dev-maybach.weibo.com (be patient) </span></li><li><span> </span></li><li class="alt"><span>Completed 1000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 2000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 3000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 4000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 5000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 6000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 7000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 8000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 9000 requests </span></li><li><span> </span></li><li class="alt"><span>Completed 10000 requests </span></li><li><span> </span></li><li class="alt"><span>Finished 10000 requests </span></li><li><span> </span></li><li class="alt"><span>Server Software: nginx/1.7.12 </span></li><li><span> </span></li><li class="alt"><span>Server Hostname: inf-dev-maybach.weibo.com </span></li><li><span> </span></li><li class="alt"><span>Server Port: 8000 </span></li><li><span> </span></li><li class="alt"><span>Document Path: /wordpress/ </span></li><li><span> </span></li><li class="alt"><span>Document Length: 9048 bytes </span></li><li><span> </span></li><li class="alt"><span>Concurrency Level: 100 </span></li><li><span> </span></li><li class="alt"><span>Time taken <span class="keyword">for</span><span> tests: 8.957 seconds </span></span></li><li><span> </span></li><li class="alt"><span>Complete requests: 10000 </span></li><li><span> </span></li><li class="alt"><span>Failed requests: 0 </span></li><li><span> </span></li><li class="alt"><span>Write errors: 0 </span></li><li><span> </span></li><li class="alt"><span>Total transferred: 92860000 bytes </span></li><li><span> </span></li><li class="alt"><span>HTML transferred: 90480000 bytes </span></li><li><span> </span></li><li class="alt"><span>Requests per second: 1116.48 [#/sec] (mean) </span></li><li><span> </span></li><li class="alt"><span>Time per request: 89.567 [ms] (mean) </span></li><li><span> </span></li><li class="alt"><span>Time per request: 0.896 [ms] (mean, across all concurrent requests) </span></li><li><span> </span></li><li class="alt"><span>Transfer rate: 10124.65 [Kbytes/sec] received </span></li></ol>
It can be seen that WordPress 4.1 is currently on this machine, and the QPS of the homepage can reach 1116.48. That is, it can handle so many requests for the homepage per second,
Now, let’s start teaching GCC and let him compile PHP7 that can run WordPress 4.1 faster. First, GCC 4.0 or above is required, but I recommend that everyone use GCC-4.8 or above (now all GCC-5.1 ).
The first step is to download the source code of PHP7, and then do ./configure. There is no difference between these
The next thing is the difference. We must first compile PHP7 for the first time so that it can generate an executable file that generates profile data:
<ol class="dp-c"><li class="alt"><span><span>$ make prof-gen <br /></span></span></li></ol>
Note that we used the prof-gen parameter (this is unique to the Makefile of PHP7, don’t try to do this in other projects :) )
Then, let’s start training GCC:
<ol class="dp-j"><li class="alt"><span><span>$ sapi/cgi/php-cgi -T </span><span class="number">100</span><span> /home/huixinchen/local/www/htdocs/wordpress/index.php >/dev/</span><span class="keyword">null</span><span> </span></span></li></ol>
That is, let php-cgi run the WordPress homepage 100 times to generate some profile information in the process.
Then, we start compiling PHP7 for the second time.
<ol class="dp-c"><li class="alt"><span><span>$ make prof-clean </span></span></li><li><span>$ make prof-<span class="keyword">use</span><span> && make install </span></span></li></ol>
Okay, it’s that simple, PGO compilation is completed, now let’s take a look at the performance of PHP7 after PGO compilation:
<ol class="dp-j"><li class="alt"><span><span>$ ab -n10000 -c </span><span class="number">100</span><span> http:</span><span class="comment">//inf-dev-maybach.weibo.com:8000/wordpress/</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>This is ApacheBench, Version <span class="number">2.3</span><span> <$Revision: </span><span class="number">655654</span><span> $> </span></span></li><li><span> </span></li><li class="alt"><span>Copyright <span class="number">1996</span><span> Adam Twiss, Zeus Technology Ltd, http:</span><span class="comment">//www.zeustech.net/</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Licensed to The Apache Software Foundation, http:<span class="comment">//www.apache.org/</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Benchmarking inf-dev-maybach.weibo.com (be patient) </span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">1000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">2000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">3000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">4000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">5000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">6000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">7000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">8000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">9000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Completed <span class="number">10000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Finished <span class="number">10000</span><span> requests </span></span></li><li><span> </span></li><li class="alt"><span>Server Software: nginx/<span class="number">1.7</span><span>.</span><span class="number">12</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Server Hostname: inf-dev-maybach.weibo.com </span></li><li><span> </span></li><li class="alt"><span>Server Port: <span class="number">8000</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Document Path: /wordpress/ </span></li><li><span> </span></li><li class="alt"><span>Document Length: <span class="number">9048</span><span> bytes </span></span></li><li><span> </span></li><li class="alt"><span>Concurrency Level: <span class="number">100</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Time taken <span class="keyword">for</span><span> tests: </span><span class="number">8.391</span><span> seconds </span></span></li><li><span> </span></li><li class="alt"><span>Complete requests: <span class="number">10000</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Failed requests: <span class="number">0</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Write errors: <span class="number">0</span><span> </span></span></li><li><span> </span></li><li class="alt"><span>Total transferred: <span class="number">92860000</span><span> bytes </span></span></li><li><span> </span></li><li class="alt"><span>HTML transferred: <span class="number">90480000</span><span> bytes </span></span></li><li><span> </span></li><li class="alt"><span>Requests per second: <span class="number">1191.78</span><span> [#/sec] (mean) </span></span></li><li><span> </span></li><li class="alt"><span>Time per request: <span class="number">83.908</span><span> [ms] (mean) </span></span></li><li><span> </span></li><li class="alt"><span>Time per request: <span class="number">0.839</span><span> [ms] (mean, across all concurrent requests) </span></span></li><li><span> </span></li><li class="alt"><span>Transfer rate: <span class="number">10807.45</span><span> [Kbytes/sec] received </span></span></li></ol>
Now it can process 1191.78 QPS per second, the improvement is ~7%. Not bad (Hey, didn’t you say 10%? How come it is 7%? Haha, as I said before, we try to analyze PGO has done some optimizations, and then manually applied some common optimizations to PHP7. So in other words, ~3% of the more common optimizations have been included in PHP7, and of course this work is still continuing).
So it’s that simple. You can use the classic scenes of your own products to train GCC. In a few simple steps, you can get improved. Why not do it :)
thanks
Editor’s note: This article is the work of PHP master——Brother Bird @Laruence, original address: http://www.laruence.com/2015/06/19/3063.html
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