Re: Weird memory usage, performance problem with 6.1_STABLE

[Lars Heidieker <lars%heidieker.de@localhost>]

On 09/19/2013 05:35 AM, Mark Davies wrote:
> I have a system that is (sometimes) used as an ftp server to serve g4u 
> disk images.  Current machine is a Dell PowerEdge R320 with 16GB 
> memory running 6.1_STABLE from yesterday.
> 
> If I get 3 ftp clients all reading the same 45GB image from it I 
> quickly get into the situation that all memory is used by something 
> and the machine becomes very unresponsive.  Below is the output of top 
> while in this state:
> 
> load averages:  3.38,  1.56,  0.68;               up 0+16:11:05               
>                           
> 14:51:52
> 43 processes: 2 runnable, 38 sleeping, 3 on CPU
> CPU0 states:  0.0% user,  0.0% nice, 23.6% system,  0.0% interrupt, 
> 76.4% idle
> CPU1 states:  0.0% user,  0.0% nice,  4.1% system,  0.0% interrupt, 
> 95.9% idle
> CPU2 states:  0.0% user,  0.0% nice, 28.5% system,  0.0% interrupt, 
> 71.5% idle
> CPU3 states:  0.0% user,  0.0% nice,  2.1% system,  0.0% interrupt, 
> 97.9% idle
> CPU4 states:  0.0% user,  0.0% nice,  3.8% system,  0.0% interrupt, 
> 96.2% idle
> CPU5 states:  0.0% user,  0.0% nice, 78.9% system,  0.0% interrupt, 
> 21.1% idle
> Memory: 15G Act, 113M Inact, 15M Wired, 29M Exec, 15G File, 112K Free
> Swap: 8192M Total, 8192M Free
> 
>   PID USERNAME PRI NICE   SIZE   RES STATE      TIME   WCPU    CPU 
> COMMAND
>     0 root     126    0     0K   29M CPU/1      3:37 99.76% 99.76% 
> [system]
>  7173 root      79    0    53M 4588K CPU/2      1:52 36.13% 36.13% 
> ftpd
>  6931 root     113    0    53M 4588K RUN/2      1:13 28.42% 28.42% 
> ftpd
>  7025 root     115    0    53M 4588K RUN/1      2:03 26.61% 26.61% 
> ftpd
>  6601 root      43    0    17M 1876K CPU/5      0:01  4.05%  4.05% top
> 
> 
> If I just run two ftp clients there seems to be about 5GB of Inactive 
> memory and performance is "fine".
> 
> Previously I had an i386 box running 5.x or 6.x doing this job and it 
> could quite happily have 10-15 clients slurping images at once.
> 
> So whats going on?
> 
> cheers
> mark
> 


Can you see which kernel thread causes high CPU usage by showing lwps in
top? (t toggles those modes)

Lars



-- 
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Mystische Erklärungen:
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   [ Die Fröhliche Wissenschaft Buch 3, 126 ]