PHP服务缓存优化原理
Nginx 根据扩展名或者过滤规则将PHP程序请求传递给解析PHP的FCGI，也就是php-fpm进程
缓存操作码（opcode）
Opcode，PHP编译后的中间文件，缓存给用户访问
当客户端请求一个PHP程序时，服务器的PHP引擎会解析该PHP程序，并将其编译为特定的操作码文件，该文件是执行PHP代码后的一种二进制文件表现形式。默认情况下，这个编译好的操作码文件由PHP引擎执行后丢弃；而操作码缓存的原理就是将编译后的操作码保存下来，并放入到共享内存里，以便再下一次调用该PHP页面时重用它，避免了相同代码的重复编译。节省了PHP引擎重复编译的时间，降低了服务器负载，同时减少了CPU和内存的开销.
常用的PHP缓存加速软件
1)xcache
经测试，xcache效率更好、社区活跃、兼容PHP版本多
2)ZendOpcache
Apache公司自主研发软件，5.5版本以后自带，加enbale-opcache编译参数直接使用，但是软件稳定性有待检测
3)eAccelerator
5.3版本以前经常使用的加速软件，随着5.5版本升级，和xcache等优秀软件的出现，社区活跃度开始下降
缓存软件首选xcahe、持续关注ZendOpcache...
xcache部署
1）下载xcache，添加为PHP扩展模块，编译安装
[root@web01 tools]# wget http://xcache.lighttpd.net/pub/Releases/3.2.0/xcache-3.2.0.tar.bz2
[root@web01 tools]# tar xf xcache-3.2.0.tar.bz2
[root@web01 tools]# cd xcache-3.2.0
[root@web01 xcache-3.2.0]# /application/php/bin/phpize
[root@web01 xcache-3.2.0]# ./configure --enable-xcache --with-php-config=/application/php/bin/php-config
[root@web01 xcache-3.2.0]# make && make install
...
Installing shared extensions: /application/php5.5.32/lib/php/extensions/no-debug-non-zts-20121212/
Installing header files: /application/php5.5.32/include/php/
2）配置php扩展生效
[root@db02 application]# vim /application/php/lib/php.ini
extension_dir = "/application/php5.5.32/lib/php/extensions/no-debug-non-zts-20121212/"
extension = memcache.so
extension = imagick.so
extension = xcache.so
3）重启php后模块生效
[root@db02 application]# /application/php/bin/php -m|grep "XCache"
XCache
XCache Cacher
4）xcache配置文件
[root@db02 ~]# cat ~/tools/xcache-3.2.0/xcache.ini|egrep -v "^;|^ " >> /application/php/lib/php.ini
[xcache-common]
extension = xcache.so #模块
[xcache.admin]
xcache.admin.enable_auth = On #开启密码认证
xcache.admin.user = "mOo"
xcache.admin.pass = "md5 encrypted password"
[xcache]
xcache.shm_scheme = "mmap" #设置Xcache如何从系统分配共享内存
xcache.size = 60M #缓存大小，0禁止缓存
xcache.count = 1 #指定将xcache切分为多少块，建议与CPU核数相同（grep -c processor /proc/cpuinfo）
xcache.slots = 8K
xcache.ttl = 0 #设置cache对象生存期TTL，0永不过期；如果上线次数多，调小
xcache.gc_interval = 0 #回收器扫描过期的对象回收内存空间的间隔，0不扫描
xcache.var_size = 4M #变量缓存，而不是opcache缓存
xcache.var_count = 1
xcache.var_slots = 8K
xcache.var_ttl = 0
xcache.var_maxttl = 0
xcache.var_gc_interval = 300
xcache.var_namespace_mode = 0
xcache.var_namespace = ""
xcache.coredump_type = 0
5）查看PHP chache加载情况
[root@db02 ~]# /application/php/sbin/php-fpm -v
PHP 5.5.32 (fpm-fcgi) (built: Jun 29 2016 11:32:56)
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.5.0, Copyright (c) 1998-2015 Zend Technologies
with XCache v3.2.0, Copyright (c) 2005-2014, by mOo
with XCache Cacher v3.2.0, Copyright (c) 2005-2014, by mOo
6）web界面配置
[root@db02 ~]# echo -n "123456"|md5sum
e10adc3949ba59abbe56e057f20f883e -
[root@db02 ~]# cp ~/tools/xcache-3.2.0/htdocs /application/nginx/html/www/xadmin -a
[root@db02 ~]# vim /application/php/lib/php.ini
[Date]
date.timezone = Asia/Chongqing
[xcache.admin]
xcache.admin.enable_auth = On
xcache.admin.user = "admin"
xcache.admin.pass = "e10adc3949ba59abbe56e057f20f883e"
[root@db02 ~]# pkill php-fpm
[root@db02 ~]# /application/php/sbin/php-fpm
ab压力测试效果
1）未加xcache之前
[root@db02 application]# ab -n 3000 -c 100 http://10.0.0.111/test_info.php
# 3000次会话请求、100并发数
Server Software: nginx/1.6.3
Server Hostname: 10.0.0.111
Server Port: 80
Document Path: /test_info.php #测试页面
Document Length: 83921 bytes #页面大小
Concurrency Level: 100 #100并发数
Time taken for tests: 7.973 seconds #整个测试持续时间
Complete requests: 3000 #完成的请求总数
Failed requests: 302 #失败的请求次数
(Connect: 0, Receive: 0, Length: 302, Exceptions: 0)
Write errors: 0
Total transferred: 252203675 bytes #整个过程的网络传输量
HTML transferred: 251762675 bytes #HTML内容传输量
Requests per second: 376.25 [#/sec] (mean) #吞吐量，每秒能够处理的并发数
Time per request: 265.779 [ms] (mean) #平均事务响应时间
Time per request: 2.658 [ms] (mean, across all concurrent requests)
#每个连接请求实际运行时间
Transfer rate: 30889.42 [Kbytes/sec] received
#平均每秒网络上的流量，可以帮助排除是否存在网络流量大导致响应时间延长的问题
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 1 3.2 0 21
Processing: 14 261 32.2 261 331
Waiting: 2 260 32.4 260 331
Total: 29 261 29.9 261 331
Percentage of the requests served within a certain time (ms)
50% 261
66% 268
75% 273
80% 276
90% 287 #90%的请求任务在287ms内完成
95% 303
98% 315
99% 322
100% 331 (longest request)
2）配置xache之后
[root@db02 application]# ab -n 3000 -c 100 http://10.0.0.111/test_info.php
Server Software: nginx/1.6.3
Server Hostname: 10.0.0.111
Server Port: 80
Document Path: /test_info.php
Document Length: 172 bytes
Concurrency Level: 100
Time taken for tests: 0.516 seconds
Complete requests: 3000
Failed requests: 0
Write errors: 0
Non-2xx responses: 3000
Total transferred: 969000 bytes
HTML transferred: 516000 bytes
Requests per second: 5819.42 [#/sec] (mean) #并发数上升为5000+
Time per request: 17.184 [ms] (mean)
Time per request: 0.172 [ms] (mean, across all concurrent requests)
Transfer rate: 1835.62 [Kbytes/sec] received
Connection Times (ms)
min mean[+/-sd] median max
Connect: 0 0 1.3 0 9
Processing: 6 17 2.1 16 21
Waiting: 0 17 2.2 16 21
Total: 7 17 1.6 16 21
Percentage of the requests served within a certain time (ms)
50% 16
66% 17
75% 18
80% 19
90% 19
95% 19
98% 20
99% 21
100% 21 (longest request)
由于是虚机测试环境，不一定十分准确，未安装xcache并发数在400-500，安装后并发数在5000左右，缓存效果提升10倍以上...