[Xenomai] kernelshark to check the CPU usage of the xenomai task.

[Xenomai] kernelshark to check the CPU usage of the xenomai task.

[박재호]

Hi, all



I'm using kernelshark to check the CPU usage of the xenomai task.



To check the cpu share of the xenomai task according to the cpu load given by Linux.

Using the stress-ng tool on Linux .

"# stress-ng -c0 -l100" 

gives 100% load to cpu, and xenomai has a run time of 750us for 1ms cycle.



Checking /proc/xenomai/stat we were able to verify the use of 75% CPU. 

However, I checked the cpu quota of xenomai and linux(stress-ng) using tracd-cmd and kernelshark 

I expected xenomai to use more cpu because its priority was higher than normal Linux, but the result was not so. 

The task that is "ecat-embedded" in the picture is the xenomai task. Why are these results coming out?



thank you for your advice.

Re: [Xenomai] kernelshark to check the CPU usage of the xenomai task.

[Jan Kiszka]

On 19.09.18 10:02, 박재호 wrote:
> Hi, all
> 
> 
> 
> I'm using kernelshark to check the CPU usage of the xenomai task.
> 
> 
> 
> To check the cpu share of the xenomai task according to the cpu load given by Linux.
> 
> Using the stress-ng tool on Linux .
> 
> "# stress-ng -c0 -l100"
> 
> gives 100% load to cpu, and xenomai has a run time of 750us for 1ms cycle.
> 
> 
> 
> Checking /proc/xenomai/stat we were able to verify the use of 75% CPU.
> 
> However, I checked the cpu quota of xenomai and linux(stress-ng) using tracd-cmd and kernelshark
> 
> I expected xenomai to use more cpu because its priority was higher than normal Linux, but the result was not so.

Are you using trace-cmd and kernelshark as-is (unmodified versions)? Then they 
lack knowledge about Xenomai and cannot visualize RT task switches properly. I 
think I once shared some patches we used in-house, but I'm not sure anymore if 
that was public.

> 
> The task that is "ecat-embedded" in the picture is the xenomai task. Why are these results coming out?
> 

Note that html-emails easily get filtered on public lists. Attach any non-text 
information you need to share in a addition to the description in a plain-text 
email.

Jan

-- 
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux