[CLUE-Tech] top and system load

[Ed Hill]

On Fri, 2002-05-10 at 20:27, Jason Friedman wrote:
> I've printed below the output from the top command:
> 
>    2:25am  up 27 days, 13:12,  7 users,  load average: 2.00, 2.00, 2.00
> 93 processes: 85 sleeping, 7 running, 0 zombie, 1 stopped
> CPU states: 42.8% user, 57.1% system,  0.0% nice,  0.0% idle
> Mem:   383960K av,  380748K used,    3212K free,    1756K shrd,   
> 15532K buff
> Swap:  265032K av,      20K used,  265012K free                  
> 208416K cached
> 
> I'm not familiar with the meaning of these numbers.  Is my system being 
> barely touched, overwhelmed, or something in the middle?


Deciphering top/ps output should be a FAQ item for all LUGs...  ;-)

Basically, heres what it says:

  - Your CPU is 100% busy with 1/2 the load due to user 
    processes and 1/2 due to kernel-space code.  You should 
    look to see if you have a "hung" process or something else 
    going on.  Take a look at which program(s) are using up 
    the CPU cycles and take it from there.

  - Your memory is nearly 100% used but this is very *NORMAL* 
    for almost *ANY* load (even very light loads) since the 
    Linux virtual memory subsystem (VM) will aggressively use 
    memory as a cache for disk access.  A better indicator of 
    a memory-congested system is to see the VM digging deeply 
    into the swap space.  Which it is not doing in your case.  
    But note that even if your system is using a lot of swap 
    space then it might just be a lot of sleeping processes.  
    Again, look into the per-process memory usage as reported 
    by top and ps.

hth,
Ed

ps - I took a look at the Process-Monitor-HOWTO.html at linuxdoc and was
disappointed by how little info it provides.  I think someone should
flesh it out a bit more...


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Edward H. Hill III, PhD    |  Email:       ed at eh3.com, ehill at mines.edu
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