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Date: Tue, 07 Jul 2009 16:11:16 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-help] pthread_create memory size
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To: Yigal Goldberger <yigal_gold@domain.hid>
Cc: xenomai@xenomai.org

Yigal Goldberger wrote:
> Hi all,
> I'm using xenomai  on kernel 2.6.29 on a powerpc based board.
> I see that when I call : 
> cat proc/meminfo
> before pthread_create and after it there is a difference of 2MB in free memory , indicating that the thread is being allocated 2MB of ram (?) .
> 
> before :
> MemTotal:       256868 kB
> MemFree:        227624 kB
> 
> After :
> MemTotal:       256868 kB
> MemFree:        225632 kB
> 
> I am calling pthread_attr_setstacksize(&attr,8192)
> before calling pthread_create so it shouldn't be the stack size .
> Is this the expected memory consuption per thread ? 
> if not, how can I reduce this ?

That is explained in the TROUBLESHOOTING guide, use ulimit -s. In fact,
I suspect the behaviour depends on the version of the glibc you use. A
better indicator of your process memory map is /proc/pid/maps.

Note that a stacksize of 8K is a bit low, such simple functions as
printf will cause stack overflows with this stack size.

-- 
                                          Gilles