CPU utilization on Dashboard vs "top"

[bengalih]

Apologies if asked before but short terms like "cpu" and "top" don't come up in search.

I have several packages installed on my RT-AC68U including nginx proxy.
I notice that my CPU utilization in the dashboard may be showing high utilization of both cores at times (80%+).
However, during this same interval, a "top" within the shell only shows my CPU at about 17%.

Can someone explain the discrepancy and is there a better way to get accurate CPU utilization in the shell (assuming the dashboard is correct)?

Thanks!

 

[ColinTaylor]

Can you post a screenshot of the top display that shows the problem.

 

[bengalih]

Can you post a screenshot of the top display that shows the problem.

Sure. Here it is.
You can see my cores on the dash show 99%/75% but the top shows 47.9%/5.7% on the two cores (press '1' at top to toggle to multi-core).
What I did notice this time is that while 'top' never seems to reach higher than 50-75% of what the dash reports for either core, when I sit there and toggle it back between total and multi-core (again, press '1') it looks like I am seeing higher numbers.
It is almost as if the CPU is being hit so hard that 'top' itself isn't even able to refresh? Like once the CPU gets close to 90%, top can't even show that and is still showing the value from when it was at 70%.
I find it strange in some regards that the dash would be able to pull these values but top would not.

In any case, ideas on how I can get more reliable CPU output from 'top', or should I assume it is more accurate than the dash?

 

[Tech Junky]

I find it strange in some regards that the dash would be able to pull these values but top would not.

Except the GUI isn't real time it's a historical delayed reading.

TOP is real time 2-5 second update period.

 

[ColinTaylor]

Sure. Here it is.
You can see my cores on the dash show 99%/75% but the top shows 47.9%/5.7% on the two cores (press '1' at top to toggle to multi-core).
What I did notice this time is that while 'top' never seems to reach higher than 50-75% of what the dash reports for either core, when I sit there and toggle it back between total and multi-core (again, press '1') it looks like I am seeing higher numbers.
It is almost as if the CPU is being hit so hard that 'top' itself isn't even able to refresh? Like once the CPU gets close to 90%, top can't even show that and is still showing the value from when it was at 70%.
I find it strange in some regards that the dash would be able to pull these values but top would not.

In any case, ideas on how I can get more reliable CPU output from 'top', or should I assume it is more accurate than the dash?

The figures on those two image are roughly the same. There will be a slight difference because of the sampling period.

top shows CPU 1 at 95.1% and CPU 2 at 68.6% (not 47.9%/5.7%) compared to the GUI's 99% and 75%. Total CPU usage in top is the sum of all items on the line apart from "idle". So you can see that a significant amount of CPU is being consumed by sirq.

 

[bengalih]

The figures on those two image are roughly the same. There will be a slight difference because of the sampling period.

top shows CPU 1 at 95.1% and CPU 2 at 68.6% (not 47.9%/5.7%) compared to the GUI's 99% and 75%. Total CPU usage in top is the sum of all items on the line apart from "idle". So you can see that a significant amount of CPU is being consumed by sirq.

Thanks - I think I knew that at some point but use it so infrequently I forgot :/