Re: Use of dual CPU?

[Adam Mercer <ramercer@gmail.com>]

On 23/05/05, Marco Calviani <mirtux@studenti.fisica.unifi.it> wrote:
> Hi,
>   i have one general question regarding the use of a dual Opteron CPU
> using a smp kernel. I'm currently running a cpu intensive program that
> use for some hours 100% of the cpu time. But having a look with top at
> the processes it seems that only one CPU is doing the work at 100%: the
> other one seems idle for most of the time.
> Here i'm posting the normal behaviour:
> 
> CPU states:  cpu    user    nice  system    irq  softirq  iowait    idle
>            total   99,0%    0,0%    1,4%   0,0%     0,0%    0,0%   99,4%
>            cpu00    0,0%    0,0%    0,4%   0,0%     0,0%    0,0%   99,5%
>            cpu01   99,0%    0,0%    0,9%   0,0%     0,0%    0,0%    0,0%
> 
> Is this behaviour right for a dual cpu machine, or there is something
> not going right?

If the program you're running is not SMP enabled then this is the
right behaviour, the running program needs to be specially written to
take advantage of a multiprocessor setup.

See the SMP Howto for more details: http://www.tldp.org/HOWTO/SMP-HOWTO.html

Cheers

Adam