Nginx性能优化CPU参数worker_cpu_affinity使用说明

官方说明：http://wiki.nginx.org/NginxHttpMainModule#worker_cpu_affinity

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。