CPU usage not correct

fering · Post by **fering** » Sun Nov 23, 2008 5:55 am

Hi,

The cpu usage graph of my linux machine shows 80% but when i look at the top command its not more then 10%. Cn it be that 80% does not take under account that my machine has 8 cpu ?

Thanks

dus001 · Post by **dus001** » Sun Nov 23, 2008 7:03 am

fering wrote:Cn it be that 80% does not take under account that my machine has 8 cpu ?

Exactly, 80 here means 80/800 -> 10%.

One quick solution is to change the graph template to divide values by 8 before rendering.

fering · Post by **fering** » Sun Nov 23, 2008 7:59 am

how can i add this devide option ? in function ? didnt see any option to devide ?

dus001 · Post by **dus001** » Sun Nov 23, 2008 11:29 am

fering wrote:how can i add this devide option ? in function ? didnt see any option to devide ?

If you choose this option, you have to:
- create a new CDEF (console -> Graph Management -> CDEFs -> Add) which does this ' / 8 ' operation
- maybe duplicate the graph template you are currently using (maybe you need to preserve it for other servers)
- in the target graph template, for each graph item set the created CDEF
- if you duplicated the graph template: update the graph to use the new template.

Post by **gandalf** » Sun Nov 23, 2008 12:36 pm

There are several approaches to ease this ask:

1. CDEF
mentioned above
Requires a CDEF and a Graph Template per "server layout" e.g. one for a 4 CPU machine, another one for a 8 CPU machine ...

2. Data Query
Verify, that you are able to query the target for the "number of CPUs"
Create a (SNMP|Script) Data Query and make the number a "<direction>input</direction>" element named nmbrCPU. Then you may use e.g. |query_nmbrCPU| in a single CDEF/Graph Template
(see 1st link of my sig for more help)
Support for this was added with cacti 087b

Reinhard

fering · Post by **fering** » Sun Nov 23, 2008 3:15 pm

thanks to all x10

plotting4fun · Post by **plotting4fun** » Tue Dec 16, 2008 10:00 am

gandalf wrote:
2. Data Query
Verify, that you are able to query the target for the "number of CPUs"
Create a (SNMP|Script) Data Query and make the number a "<direction>input</direction>" element named nmbrCPU. Then you may use e.g. |query_nmbrCPU| in a single CDEF/Graph Template
(see 1st link of my sig for more help)
Support for this was added with cacti 087b

Reinhard

That's very interesting ! Somebody has done a template like this ?

Cacti

CPU usage not correct

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