load average with multi-core CPU's

Rodrigo Gonzalez rjgonzale at estrads.com.ar
Thu Sep 22 20:59:43 UTC 2011

On 09/22/2011 04:29 PM, Mark Felder wrote:
> On Thu, 22 Sep 2011 10:22:43 -0500, Henry M <henry95 at gmail.com> wrote:
>> Hi all,
>> Can someone explain, or point me to correct documentation on what the 
>> load
>> average on top/uptime is actually displaying?
> Load average is "average number of processes in the run queue" for the 
> 1, 5, and 15 minute intervals. If you have a quad core CPU a 4.00 load 
> average means you've been keeping the CPU busy at 100%.
Not exactly as I understand it....IO (disk, network or whatever) affects 
it too...
It is the number of task waiting in queue to be run....but IO is 
important...if 2 processes are waiting for IO and it is completely 
saturated they will be kept in queue so load will get higher
I think there are other things that affect load average but are over my 
current knowledge...


Rodrigo Gonzalez

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