Nginx性能优化CPU参数worker_cpu_affinity使用说明
官方说明：
worker_cpu_affinity
Syntax:worker_cpu_affinity cpumask [cpumask...]
Default:none
Linux only.
With this option you can bind the worker process to a CPU, it calls sched_setaffinity().
For example,
worker_processes 4;worker_cpu_affinity 0001 0010 0100 1000;
Bind each worker process to one CPU only.
worker_processes 2;worker_cpu_affinity 0101 1010;
Bind the first worker to CPU0/CPU2, bind the second worker to CPU1/CPU3. This is suitable for HTT.
一个服务器为Q9300单cpu，4核心，于是可以直接用官方的配置：worker_cpu_affinity 0001 0010 0100 1000;
效果如下，看起来每个cpu核心都比较平均：
top - 21:17:56 up 4 days, 7:41, 3 users, load average: 0.25, 0.44, 0.47
Tasks: 238 total, 1 running, 237 sleeping, 0 stopped, 0 zombie
Cpu0 : 0.3%us, 0.3%sy, 0.0%ni, 94.2%id, 5.2%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 0.3%us, 0.0%sy, 0.0%ni, 96.2%id, 0.6%wa, 0.6%hi, 2.2%si, 0.0%st
Cpu2 : 0.3%us, 0.0%sy, 0.0%ni, 93.5%id, 5.5%wa, 0.0%hi, 0.6%si, 0.0%st
Cpu3 : 0.0%us, 0.0%sy, 0.0%ni, 96.5%id, 3.5%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 8119372k total, 3641940k used, 4477432k free, 504900k buffers
Swap: 8385888k total, 10664k used, 8375224k free, 2407512k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
30743 apache 20 0 6632 3800 812 S 0.3 0.0 0:00.51 nginx
30745 apache 20 0 7156 4384 812 S 0.3 0.1 0:00.85 nginx
以下文字来源于：http://www.chengyongxu.com/blog/nginx的worker_cpu_affinity详解/
配置文件中的worker_cpu_affinity可以用来绑定每个nginx进程所使用的CPU
官方的解释是：
#----------------------------引用文字-开始----------------------------
Syntax: worker_cpu_affinity cpumask [cpumask...]
Default: none
Linux only.
With this option you can bind the worker process to a CPU, it calls sched_setaffinity().
For example,
worker_processes 4;
worker_cpu_affinity 0001 0010 0100 1000;
Bind each worker process to one CPU only.
worker_processes 2;
worker_cpu_affinity 0101 1010;
Bind the first worker to CPU0/CPU2, bind the second worker to CPU1/CPU3. This is suitable for HTT.
#----------------------------引用文字-结束----------------------------
最关键的地方没说清楚，怎样来表示每个CPU？
经过漫天的搜索和多次尝试发现
那么，16核的cpu每个进程分配到一个cpu就应该是
测试一下，用别的服务器发出大量请求
ab -n 20000 -k http://您的ip或域名/index.php
在被测试的服务器上查看cpu状态
top
然后按1
可以看到每个cpu都在工作了。