Re: [Xenomai] Default options in the debian package

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 04/22/2013 09:18 AM, Leopold Palomo-Avellaneda wrote:

> A Divendres, 19 d'abril de 2013, Gilles Chanteperdrix va escriure:
>> On 04/19/2013 01:46 PM, Leopold Palomo-Avellaneda wrote:
>>
>>> [1] 
>>> http://lists.mech.kuleuven.be/pipermail/orocos-users/2013-
> April/006986.html
>>
>>
>> Hi,
>>
>> that link does not tell us why you need this option. And that would be
>> the most important information.
> 
> :-)
> 
> you are right. I have pointed vague information about that. The complete 
> thread commented that some people are getting errors using orocos with 
> xenomai. Orocos use intensively the plugin architecture. As you can see in 
> this thread:
> 
> http://www.orocos.org/forum/orocos/orocos-users/problem-orocos-under-xenomai
> 
> some user point that the solution to load the plugin is to activate this 
> option in xenomai libs.
> 
>> If what you need to disable is TLS, then configuring xenomai with
>> --without-__thread is sufficient
>>
>> If what you need is to avoid the main thread shadowing, we are not going
>> to configure xenomai with --enable-dlopen-skins as it breaks otherwise
>> conformant applications, but we can add an environment variable like
>> XENO_PTHREAD_NO_AUTO_SHADOW to allow supporting both situations.
>>
> 
> I don't know if this is a solution, it overpass my knowledge. I would like to 
> put the detail that, under my subjective point of view, without numerical 
> data, the orocos users (and cnc users) are the main users of the debian 
> package. If, we activate that option and we solve this issue, no package 
> recompilation are needed, that's all. 
> 
> I don't know the deep repercussion of that decision. Jan Kiszka said in 
> another mail:
> 
>> default is a micro-performance degradation (likely not an issue) and the 
> lacking auto-shadowing of the main thread when using POSIX skins
> 
> You are the main developers, your decisions are the most important, but I 
> think that a lot of people activate that, at least the users that use that 
> debian package.


The problem is that if we do not shadow the main thread, we break
programs that used to work, and also break programs for reasons which
are hard to understand for a new-comer. Hence the question, would not
--without__thread be sufficient for Orocos? Only an Orocos user has the
answer to this question.

-- 
                                                                Gilles.