Regarding the CPU Usage in arm board for an example of QTableView while scrolling

Pradeep Kumar

Hi,

I have a QTableview , i have used QStandardItemModel as a model , and added to QTableView, while scrolling . i have observed the CPU % gradually increases to 100%. same does not hold good in Desktop.

May i know what id the reason?.
Guidance will help me.
Thanks.

VRonin

this is due to paint being called frequently an in turn it having to query the model for data. fast scrolling brings my CPU usage to 10% (intel i7 3.6GHz). Do you use custom delegates or just pure Qt classes?

Pradeep Kumar

I am using Qt Classes , i am not using any custom delegates. Is their any difference in working in Desktop and Arm Board with the the same program?.

SGaist

Hi,

Depends on your Arm board, but it's likely less powerful than your desktop machine CPU/GPU wise. What board are you running your application on ?

Pradeep Kumar

I am using ARM 11. The application is running on ARM 11.

SGaist

That's an architecture. There are lots of ARM11 based processors/boards. What are you using exactly ?

Pradeep Kumar

Visiontek Pos device

SGaist

Can you give a link to the device description ?

Pradeep Kumar

The link is here , here is the link for the specifications of the device

SGaist

Ok, so you have have a single core 1GHz processor with 512MB of RAM.

What size is your model ?

Pradeep Kumar

@SGaist

The size is 320 , 240.

SGaist

I meant the data model

Pradeep Kumar

@SGaist

can u brief me up regarding the data model. what is it.?.

jsulm

@Pradeep-Kumar From your first post: "i have used QStandardItemModel as a model" - so I guess the question is how big is this model (how many elements does it contain)?

Pradeep Kumar

The standard item model data was having 3 columns and the rows values depends on DB values. it will increase as per the db values.

SGaist

Then what is the usual size of your database ?

Pradeep Kumar

Without Db also i tried the same, again i have observed the CPU % gradually increases to 100%. i didnt understand the behaviour. please guide me.

SGaist

Without any test case to run, it's pretty much impossible to help you get further. There's also no information about what else is running on your target or what your application does that might or might not be influenced by what happens in your GUI.

Pradeep Kumar

Their was some daemon process running, when i checked the application.

SGaist

Use top to see which is the processor hog: Likely your application but you have to verify to be sure.

After that confirmation, it would also be useful if you could describe precisely how you trigger that CPU load.

On a side note: which version of Qt are you using ? With which plugin ?