cpu usage in 7.0
Ivan Voras
ivoras at freebsd.org
Sun Feb 24 21:00:36 UTC 2008
Kris Kennaway wrote:
> Hugo Silva wrote:
>> Kris Kennaway wrote:
>>> Barney Cordoba wrote:
>>>> I have a dual core system running 7.0 and I can't get
>>>> top to show more than 100% usage no matter how I
>>>> hammer it. My MAC shows over 100% often, but its not
>>>> clear if top is averaging the 2 cpus or just not going
>>>> over 100, or just showing 1 of the cpus.
>>>
>>> 100% in FreeBSD means "all of your CPUs are completely active". It
>>> is hard to exceed this amount :-)
>>
>> You should see my production mysql going over 458% on service startup,
>> on a quad core server :-)
>
> That is a multithreaded process using multiple CPUs, not the total CPU
> statistics (first line of top(1)).
So how does a multithreaded process get 458% CPU on a quad-core machine?
:) (Really, I want to know; I thought thread CPU accounting was fixed in
7.x. Unless I'm mistaken, 4 CPU-intensive threads in a single process
should account as 4 CPU-intensive single-thread processes; i.e. each
could only take up to 100% of a core/CPU, accounting for NCPU*100% total).
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