[OE-core] [yocto] CPU Load

[Andre McCurdy]

On Tue, Mar 27, 2018 at 4:44 AM, Ryan Meulenkamp
<Ryan.Meulenkamp at nedap.com> wrote:
> Hi y'all,
>
> I have some questions about CPU load and performance, but first some
> background information.
>
> We have small embedded system running an openembedded classic (Angström)
> distro. Now to get ourselves up-to-date we started working on a new
> iteration of the OS based on openembedded core and Yocto. It is nearly
> finished now, if it weren't for one problem: The CPU load (/proc/loadavg) of
> the core/yocto based OS is more than double that of the classic/Angström OS.
>
> So the way I see it this could be caused by a number of factors:
>
>  - loadavg's calculation changed
>  - certain newer versions of applications run heavier
>  - The kernel itself is heavier (we upgraded from 2.6.35.14+ to 4.9.28+)
>   - Possibly caused by some configs
>  - ...
>
> My question: is there something that changed since OE-classic that you know
> could be the cause of this? If not, how would I go about finding the cause?
> I don't think the top command is sufficient for this, because it's precision
> is such that many processes' CPU usage just become 0%.

You don't say what the CPU doubled from or too. 1% to 2%, or 50% to
100% ? Unless the absolute increase is very small, you can probably
ignore the processes which top reports as 0%.

Does the new build have any significant processes running which
weren't there in the old build? Or is it the same basic set of apps
running in each?

> Also, both top and
> htop cause huge cpu loads themselves.
>
> Any tips and tricks would be welcome!
>
> Thanks in advance!
>
> Ryan
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