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Date: Thu, 06 Feb 2014 17:35:30 +0100
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai] High CPU load using q_send under pSOS skin
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To: Marcel van Mierlo <marcel.vanmierlo@marel.com>
Cc: xenomai@xenomai.org

On 02/06/2014 05:25 PM, Marcel van Mierlo wrote:
> Hi,
>
> I've been investigating this for a couple of days and would really
> appreciate some insight
> on what might be going on or what I can do to progress this...
>
> I am porting a legacy pSOS application - to Xenomai on BeagleBoard Black
> 3.8 kernel
> and have noticed %CPU (via. top) of MAIN around 40% when using q_send,
> and doing no "work".
>
> Surprisingly,  if I add a printf() and fflush() to the task body then
> the CPU drops down to < 1%.
>
> I've checked compile options, nothing obviously wrong. Here is the
> (abridged) body of the task.
> It just provides a periodic message for watchdog purposes.
>
>
> [%CPU ~%40]
> while{1}
> {
>       q_send(ulCanTQid, (INT32 *)&oCanMsg);
>       tm_wkafter(100);  // ~100ms

Have you checked that the comment is right? Are you sure you are not 
sleeping 100ns ?

-- 
					    Gilles.