worker cpu balance

[Igor Sysoev]

On Sun, Apr 13, 2008 at 03:04:20AM +0200, Aleksandar Lazic wrote:

> Hi all,
> 
> during the testing with the donated 10GB network cards of Myricom to the
> haproxy project http://haproxy.1wt.eu/ I have asked the author of this
> nice peace of SW if he will be so pleasent to run a test with nginx
> instead of tux. He was ;-))
> 
> Here the description of his test with haproxy
> http://haproxy.1wt.eu/10g.html and now what he have send me back from
> his tests with nginx.
> 
> ---
> It works fast. Since it uses sendfile, it is as fast as Tux on large
> files (>= 1MB), and saturates 10 Gbps with 10% of CPU with 1MB files.
> 
> However, it does not scale on multiple CPUs, whatever the number of
> worker_processes. I've tried 1, 2, 8, ... The processes are quite there,
> but something's preventing them from sharing a resource since the
> machine never goes beyond 50% CPU used (it's a dual core). Sometimes,
> "top" looks like this :
> 
> Tasks: 189 total,   3 running, 186 sleeping,   0 stopped,   0 zombie
>  Cpu0 :  40.3% user,  55.2% system,   0.0% nice,   4.5% idle,   0.0% IO-wait
>  Cpu1 :   2.7% user,   1.3% system,   0.0% nice,  96.0% idle,   0.0% IO-wait
> Mem:   2072968k total,    92576k used,  1980392k free,    11604k buffers
> Swap:        0k total,        0k used,        0k free,    25656k cached
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  Command   
>  1984 nobody    20   0  2980  996  492 S 34.7  0.0   0:49.85 nginx.bin 
>  1986 nobody    20   0  2980  992  488 S 34.7  0.0   0:51.91 nginx.bin 
>  1980 nobody    20   0  2980  996  492 S 25.8  0.0   0:47.29 nginx.bin 
>  1983 nobody    20   0  2980  996  492 S  2.0  0.0   0:48.07 nginx.bin 
>  1988 nobody    20   0  2980  996  492 R  2.0  0.0   0:45.75 nginx.bin 
> 
> Sometime it looks like this :
> 
> Tasks: 188 total,   2 running, 186 sleeping,   0 stopped,   0 zombie
>  Cpu0 :  12.7% user,  12.7% system,   0.0% nice,  74.6% idle,   0.0% IO-wait
>  Cpu1 :  32.4% user,  39.4% system,   0.0% nice,  28.2% idle,   0.0% IO-wait
> Mem:   2072968k total,    92820k used,  1980148k free,    11604k buffers
> Swap:        0k total,        0k used,        0k free,    25660k cached
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  Command   
>  1985 nobody    20   0  2980  996  492 R 53.7  0.0   0:48.14 nginx.bin 
>  1982 nobody    20   0  2980  992  488 S 31.8  0.0   0:39.40 nginx.bin 
>  1986 nobody    20   0  2980  992  488 S  8.0  0.0   0:54.71 nginx.bin 
>  1988 nobody    20   0  2980  996  492 S  5.0  0.0   0:48.79 nginx.bin 
>  1983 nobody    20   0  2980  996  492 S  2.0  0.0   0:52.20 nginx.bin 

Try

events {
    accept_mutex   off;
    ...


-- 
Igor Sysoev
http://sysoev.ru/en/