目前我安装的 Homestead 虚拟机版本是 2.1.8：

该版本 Homestead 上预装的 PHP 版本是 5.6.15：

我们使用 ab 命令（Apache 提供的性能测试工具）在该版本中测试 Laravel 应用（以目前正在讲的使用Laravel开发的博客应用为例）性能，我们模拟 10000 次请求，100 个并发进行压力测试：

ab -n 10000 -c 100 http://blog.app/

运行结果如下：

This is ApacheBench, Version 2.3 <$Revision: 1638069 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking blog.app (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/1.8.0
Server Hostname: blog.app
Server Port: 80

Document Path: /
Document Length: 324 bytes

Concurrency Level: 100
Time taken for tests: 69.354 seconds
Complete requests: 10000
Failed requests: 0
Total transferred: 19851388 bytes
HTML transferred: 10230000 bytes
Requests per second: 144.19 [#/sec] (mean)
Time per request: 693.545 [ms] (mean)
Time per request: 6.935 [ms] (mean, across all concurrent requests)
Transfer rate: 279.52 [Kbytes/sec] received

Connection Times (ms)
                  min  mean[+/-sd]  median  max
Connect:       0       0     0.2                 0      3
Processing: 17    684   319.1           588   2720
Waiting:      17     684   319.1           588   2720
Total:          20     684   319.1           588   2720

Percentage of the requests served within a certain time (ms)
 50%      588
 66%      695
 75%      842
 80%      933
 90%    1155
 95%    1321
 98%    1545
 99%    1813
 100%  2720 (longest request)

这里我们要关注的是红色加粗的文字，即每秒处理请求数，这是衡量系统性能的关键指标。根据系统及硬件配置的差异，数据会有些出入。

现在我们按照Laravel Homestead 现在支持 PHP 7 了这一节所述将 Homestead 中的 PHP 升级到 7.0 版本。

使用 vagrant ssh 登录到新添加的 homestead-7 虚拟机，查看 PHP 版本信息是否正确：

此时在浏览器中访问 http://blog.app 会报错，因为新安装的 Homestead 数据库数据为空，需要登录到虚拟机运行如下命令运行迁移并填充数据：

php artisan migrate 
php artisan db:seed

再次访问就OK了，好了我们继续使用同样的 ab 命令进行压力测试：

ab -n 10000 -c 100 http://blog.app/

运行结果如下：

This is ApacheBench, Version 2.3 <$Revision: 1638069 $>
Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/
Licensed to The Apache Software Foundation, http://www.apache.org/

Benchmarking blog.app (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/1.8.0
Server Hostname: blog.app
Server Port: 80

Document Path: /
Document Length: 324 bytes

Concurrency Level: 100
Time taken for tests: 45.032 seconds
Complete requests: 10000
Failed requests: 0
Total transferred: 20101202 bytes
HTML transferred: 10230000 bytes
Requests per second: 222.06 [#/sec] (mean)
Time per request: 450.319 [ms] (mean)
Time per request: 4.503 [ms] (mean, across all concurrent requests)
Transfer rate: 435.91 [Kbytes/sec] received

Connection Times (ms)
                  min  mean[+/-sd]  median   max
Connect:       0       0     0.2                 0       4
Processing: 11    443   252.8           379   1978
Waiting:      11     443   252.8           379   1978
Total:          15     443   252.8           379   1978

Percentage of the requests served within a certain time (ms)
 50%      379
 66%      517
 75%      590
 80%      631
 90%      795
 95%      938
 98%    1060
 99%    1229
 100%  1978 (longest request)

经过对比，同一个 Laravel 应用在 PHP 7.0 下的性能比 PHP 5.6 提高了54%，这是一个很显著的性能提升，当然环境不同数据会有所出入，而且还有更大的提升空间，更多关于 PHP 7.0 的性能调优，可参考 Laruence 的这篇文章：让PHP7达到最高性能的几个Tips。