GCC PGO让你的PHP7更快

我们一直致力于提升PHP7的性能 上个月我们注意到GCC的PGO能在Wordpress上能带来近10%的性能提升 这个让我们很激动.

然而 PGO正如名字所说(Profile Guided Optimization 有兴趣的可以Google) 他需要用一些用例来获得反馈 也就是说这个优化是需要和一个特定的场景绑定的.

你对一个场景的优化 也许在另外一个场景就事与愿违了. 它不是一个通用的优化. 所以我们不能简单的就包含这些优化 也无法直接发布PGO编译后的PHP7.

当然 我们正在尝试从PGO找出一些共性的优化 然后手工Apply到PHP7上去 但这个很明显不能做到针对一个场景的特别优化所能达到的效果 所以我决定写这篇文章简单介绍下怎么使用PGO来编译PHP7 让你编译的PHP7能特别的让你自己的独立的应用变得更快.

首先 要决定的就是拿什么场景去Feedback GCC 我们一般都会选择: 在你要优化的场景中: 访问量最大的 耗时最多的 资源消耗最重的一个页面.

拿Wordpress为例 我们选择Wordpress的首页(因为首页往往是访问量最大的).

我们以我的机器为例:

 

 

Intel(R) Xeon(R) CPU X5687 @ 3.60GHz X 16(超线程) 48G Memory 12        Intel(R) Xeon(R) CPU           X5687  @ 3.60GHz X 16(超线程)       48G Memory

php-fpm 采用固定32个worker opcache采用默认的配置(一定要记得加载opcache)

以wordpress 4.1为优化场景..

首先我们来测试下目前WP在PHP7的性能(ab -n 10000 -c 100):

 

$ ab -n 10000 -c 100 http://inf-dev-maybach.weibo.com:8000/wordpress/ This is ApacheBench Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss Zeus Technology Ltd http://www.zeustech.net/ Licensed to The Apache Software Foundation http://www.apache.org/ Benchmarking inf-dev-maybach.weibo.com (be patient) Completed 1000 requests Completed 2000 requests Completed 3000 requests Completed 4000 requests Completed 5000 requests Completed 6000 requests Completed 7000 requests Completed 8000 requests Completed 9000 requests Completed 10000 requests Finished 10000 requests Server Software: nginx/1.7.12 Server Hostname: inf-dev-maybach.weibo.com Server Port: 8000 Document Path: /wordpress/ Document Length: 9048 bytes Concurrency Level: 100 Time taken for tests: 8.957 seconds Complete requests: 10000 Failed requests: 0 Write errors: 0 Total transferred: 92860000 bytes HTML transferred: 90480000 bytes Requests per second: 1116.48 [#/sec] (mean) Time per request: 89.567 [ms] (mean) Time per request: 0.896 [ms] (mean across all concurrent requests) Transfer rate: 10124.65 [Kbytes/sec] received 123456789101112131415161718192021222324252627282930313233343536 $ ab -n 10000 -c 100 http://inf-dev-maybach.weibo.com:8000/wordpress/This is ApacheBench Version 2.3 <$Revision: 655654 $>Copyright 1996 Adam Twiss Zeus Technology Ltd http://www.zeustech.net/Licensed to The Apache Software Foundation http://www.apache.org/ Benchmarking inf-dev-maybach.weibo.com (be patient)Completed 1000 requestsCompleted 2000 requestsCompleted 3000 requestsCompleted 4000 requestsCompleted 5000 requestsCompleted 6000 requestsCompleted 7000 requestsCompleted 8000 requestsCompleted 9000 requestsCompleted 10000 requestsFinished 10000 requests Server Software:        nginx/1.7.12Server Hostname:        inf-dev-maybach.weibo.comServer Port:            8000 Document Path:          /wordpress/Document Length:        9048 bytes Concurrency Level:      100Time taken for tests:   8.957 secondsComplete requests:      10000Failed requests:        0Write errors:           0Total transferred:      92860000 bytesHTML transferred:       90480000 bytesRequests per second:    1116.48 [#/sec] (mean)Time per request:       89.567 [ms] (mean)Time per request:       0.896 [ms] (mean across all concurrent requests)Transfer rate:          10124.65 [Kbytes/sec] received

可见Wordpress 4.1 目前在这个机器上 首页的QPS可以到1116.48. 也就是每秒钟可以处理这么多个对首页的请求

现在 让我们开始教GCC 让他编译出跑Wordpress4.1更快的PHP7来 首先要求GCC 4.0以上的版本 不过我建议大家使用GCC-4.8以上的版本(现在都GCC-5.1了).

第一步 自然是下载PHP7的源代码了 然后做./configure. 这些都没什么区别

接下来就是有区别的地方了 我们要首先第一遍编译PHP7 让它生成会产生profile数据的可执行文件:

 

$ make prof-gen 1 $ make prof-gen

注意 我们用到了prof-gen参数(这个是PHP7的Makefile特有的 不要尝试在其他项目上也这么搞哈  )

然后 让我们开始训练GCC:

 

$ sapi/cgi/php-cgi -T 100 /home/huixinchen/local/www/htdocs/wordpress/index.php >/dev/null 1 $ sapi/cgi/php-cgi -T 100 /home/huixinchen/local/www/htdocs/wordpress/index.php >/dev/null

也就是让php-cgi跑100遍wordpress的首页 从而生成一些在这个过程中的profile信息.

然后 我们开始第二次编译PHP7.

 

$ make prof-clean $ make prof-use && make install 12 $ make prof-clean$ make prof-use && make install

也就是让php-cgi跑100遍wordpress的首页 从而生成一些在这个过程中的profile信息.

然后 我们开始第二次编译PHP7.

 

$ make prof-clean $ make prof-use && make install 12 $ make prof-clean$ make prof-use && make install

好的 就这么简单 PGO编译完成了 现在我们看看PGO编译以后的PHP7的性能:

$ ab -n10000 -c 100 http://inf-dev-maybach.weibo.com:8000/wordpress/ This is ApacheBench Version 2.3 <$Revision: 655654 $> Copyright 1996 Adam Twiss Zeus Technology Ltd http://www.zeustech.net/ Licensed to The Apache Software Foundation http://www.apache.org/ Benchmarking inf-dev-maybach.weibo.com (be patient) Completed 1000 requests Completed 2000 requests Completed 3000 requests Completed 4000 requests Completed 5000 requests Completed 6000 requests Completed 7000 requests Completed 8000 requests Completed 9000 requests Completed 10000 requests Finished 10000 requests Server Software: nginx/1.7.12 Server Hostname: inf-dev-maybach.weibo.com Server Port: 8000 Document Path: /wordpress/ Document Length: 9048 bytes Concurrency Level: 100 Time taken for tests: 8.391 seconds Complete requests: 10000 Failed requests: 0 Write errors: 0 Total transferred: 92860000 bytes HTML transferred: 90480000 bytes Requests per second: 1191.78 [#/sec] (mean) Time per request: 83.908 [ms] (mean) Time per request: 0.839 [ms] (mean across all concurrent requests) Transfer rate: 10807.45 [Kbytes/sec] received 123456789101112131415161718192021222324252627282930313233343536 $ ab -n10000 -c 100 http://inf-dev-maybach.weibo.com:8000/wordpress/This is ApacheBench Version 2.3 <$Revision: 655654 $>Copyright 1996 Adam Twiss Zeus Technology Ltd http://www.zeustech.net/Licensed to The Apache Software Foundation http://www.apache.org/ Benchmarking inf-dev-maybach.weibo.com (be patient)Completed 1000 requestsCompleted 2000 requestsCompleted 3000 requestsCompleted 4000 requestsCompleted 5000 requestsCompleted 6000 requestsCompleted 7000 requestsCompleted 8000 requestsCompleted 9000 requestsCompleted 10000 requestsFinished 10000 requests Server Software:        nginx/1.7.12Server Hostname:        inf-dev-maybach.weibo.comServer Port:            8000 Document Path:          /wordpress/Document Length:        9048 bytes Concurrency Level:      100Time taken for tests:   8.391 secondsComplete requests:      10000Failed requests:        0Write errors:           0Total transferred:      92860000 bytesHTML transferred:       90480000 bytesRequests per second:    1191.78 [#/sec] (mean)Time per request:       83.908 [ms] (mean)Time per request:       0.839 [ms] (mean across all concurrent requests)Transfer rate:          10807.45 [Kbytes/sec] received

现在每秒钟可以处理1191.78个QPS了 提升是~7%. 还不赖哈(咦 你不是说10%么? 怎么成7%了? 呵呵 正如我之前说过 我们尝试分析PGO都做了些什么优化 然后把一些通用的优化手工Apply到PHP7中. 所以也就是说 那~3%的比较通用的优化已经包含到了PHP7里面了 当然这个工作还在继续).

于是就这么简单 大家可以用自己的产品的经典场景来训练GCC 简单几步 获得提升 何乐而不为呢

thanks

作者信息

作者: Laruence

本文地址: http://www.laruence.com/2015/06/19/3063.html

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