[Xenomai-core] realtime pipes

[Xenomai-core] realtime pipes

[Jan-Erik Lange]

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Hello,
 
it is possible to access a real-time pipe /dev/rtpx within the kernel space of Linux? Since there is no open function? 
 
Is it therefore possible to communicate between the Xenomai Kernel space and the Linux Kernel space?
 
Best regards
 
Jan 		 	   		  

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Re: [Xenomai-core] realtime pipes

[Gilles Chanteperdrix]

On 01/15/2012 01:36 PM, Jan-Erik Lange wrote:
> 
> Hello,
> 
> it is possible to access a real-time pipe /dev/rtpx within the kernel
> space of Linux? Since there is no open function?

Real-time pipes are deprecated.

> 
> Is it therefore possible to communicate between the Xenomai Kernel
> space and the Linux Kernel space?

As mentioned several time, using anything else in kernel-space than the
RTDM API is deprecated. If you are interested in the services the RTDM
api offers, see:

http://www.xenomai.org/documentation/xenomai-2.6/html/api/group__driverapi.html

For instance, you can see a section named "non-real-time signalling
services", which probably answers your question.

-- 
                                                                Gilles.

[Xenomai-core] FW: realtime pipes

[Jan-Erik Lange]

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From: jan0385@domain.hid
To: gilles.chanteperdrix@xenomai.org
Subject: RE: [Xenomai-core] realtime pipes
Date: Sun, 15 Jan 2012 19:38:01 +0100






 


> Date: Sun, 15 Jan 2012 18:37:23 +0100
> From: gilles.chanteperdrix@xenomai.org
> To: jan0385@domain.hid
> CC: xenomai@xenomai.org
> Subject: Re: [Xenomai-core] realtime pipes
> 
> On 01/15/2012 01:36 PM, Jan-Erik Lange wrote:
> > 
> > Hello,
> > 
> > it is possible to access a real-time pipe /dev/rtpx within the kernel
> > space of Linux? Since there is no open function?
> 
> Real-time pipes are deprecated.
> 
 
 
Are realtime pipes deprecated at all or only in kernel space?
 And why is the documentation so obsolete? I didn't heard this information since yet..
 

> > 
> > Is it therefore possible to communicate between the Xenomai Kernel
> > space and the Linux Kernel space?
> 
> As mentioned several time, using anything else in kernel-space than the
> RTDM API is deprecated. If you are interested in the services the RTDM
> api offers, see:
> 
> http://www.xenomai.org/documentation/xenomai-2.6/html/api/group__driverapi.html
> 
> For instance, you can see a section named "non-real-time signalling
> services", which probably answers your question.
> 
> -- 
> Gilles.
 		 	   		  

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Re: [Xenomai-core] realtime pipes

[Makarand Pradhan]

Hi,

"Real-time pipes are deprecated."

We use a lot of rt pipes. So, can you pl elaborate on this? I would 
highly appreciate if you can comment on the following.

1. When will the rt pipe interface be removed? Any time frame?
2. Would like to understand the reason for deprecating the interface.

Thanks and Rgds,
Mak.


On 15/01/12 12:37 PM, Gilles Chanteperdrix wrote:
> Real-time pipes are deprecated.


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Re: [Xenomai-core] realtime pipes

[Philippe Gerum]

On 01/16/2012 03:25 PM, Makarand Pradhan wrote:
> Hi,
>
> "Real-time pipes are deprecated."
>
> We use a lot of rt pipes. So, can you pl elaborate on this? I would
> highly appreciate if you can comment on the following.
>
> 1. When will the rt pipe interface be removed? Any time frame?

Xenomai 3. Xenomai 2.x will keep them forever.

> 2. Would like to understand the reason for deprecating the interface.
>

- Because there is a better socket-based API implemented by the RTIPC 
driver w/ the XDDP protocol, which does not require running application 
level code in kernel space (RT_PIPE is definitely an application level 
API). This new interface is available since Xenomai 2.5.x. It is 
functionally 100% equivalent to the legacy RT_PIPE API.

- Because no support will be provided in Xenomai 3 for running 
application level code in kernel space, so RT_PIPE have to go from 
kernel space. However, RT_PIPE are still part of the user-space API of 
Xenomai 3, interfacing with XDDP endpoints in kernel space.

I'm really referring to application level code, by contrast to RTDM 
driver level code which will obviously remain a first-class citizen in 
kernel space.

See:

o http://www.xenomai.org/index.php/Xenomai:Roadmap

o 
http://www.xenomai.org/documentation/xenomai-2.6/html/api/group__rtipc.html

o examples/rtdm/profiles/ipc in the Xenomai distro

> Thanks and Rgds,
> Mak.
>
>
> On 15/01/12 12:37 PM, Gilles Chanteperdrix wrote:
>> Real-time pipes are deprecated.
>
>


-- 
Philippe.

Re: [Xenomai-core] realtime pipes

[Makarand Pradhan]

Thanks Philippe.

To ensure that I understand correctly, let me rephrase my understanding.

In 3.0, the rt_pipe_create and friends will cease to exist. We have to 
start using the sockets  with domain AF_RTIPC and protocol  
IPCPROTO_XDDP instead.

Is that a correct statement?

Rgds,
Mak.

On 16/01/12 09:35 AM, Philippe Gerum wrote:
> On 01/16/2012 03:25 PM, Makarand Pradhan wrote:
>> Hi,
>>
>> "Real-time pipes are deprecated."
>>
>> We use a lot of rt pipes. So, can you pl elaborate on this? I would
>> highly appreciate if you can comment on the following.
>>
>> 1. When will the rt pipe interface be removed? Any time frame?
> Xenomai 3. Xenomai 2.x will keep them forever.
>
>> 2. Would like to understand the reason for deprecating the interface.
>>
> - Because there is a better socket-based API implemented by the RTIPC
> driver w/ the XDDP protocol, which does not require running application
> level code in kernel space (RT_PIPE is definitely an application level
> API). This new interface is available since Xenomai 2.5.x. It is
> functionally 100% equivalent to the legacy RT_PIPE API.
>
> - Because no support will be provided in Xenomai 3 for running
> application level code in kernel space, so RT_PIPE have to go from
> kernel space. However, RT_PIPE are still part of the user-space API of
> Xenomai 3, interfacing with XDDP endpoints in kernel space.
>
> I'm really referring to application level code, by contrast to RTDM
> driver level code which will obviously remain a first-class citizen in
> kernel space.
>
> See:
>
> o http://www.xenomai.org/index.php/Xenomai:Roadmap
>
> o
> http://www.xenomai.org/documentation/xenomai-2.6/html/api/group__rtipc.html
>
> o examples/rtdm/profiles/ipc in the Xenomai distro
>
>> Thanks and Rgds,
>> Mak.
>>
>>
>> On 15/01/12 12:37 PM, Gilles Chanteperdrix wrote:
>>> Real-time pipes are deprecated.
>>
>


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Re: [Xenomai-core] realtime pipes

[Philippe Gerum]

On 01/16/2012 04:09 PM, Makarand Pradhan wrote:
> Thanks Philippe.
>
> To ensure that I understand correctly, let me rephrase my understanding.
>
> In 3.0, the rt_pipe_create and friends will cease to exist. We have to
> start using the sockets with domain AF_RTIPC and protocol IPCPROTO_XDDP
> instead.
>
> Is that a correct statement?

Basically, yes. In addition, X3 will keep the RT_PIPE interface for the 
-rt endpoint available on the application-side, by wrapping a XDDP 
socket to a RT_PIPE descriptor under the hood. In kernel space however, 
the RT_PIPE API to create -rt endpoints won't be available anymore, one 
will have to create them via the rtdm_socket/rt_dev_socket calls.

In any case, the API for the non-rt side does not change, i.e. POSIX 
file I/O calls will still be the way to interface with the -rt endpoint.

>
> Rgds,
> Mak.
>
> On 16/01/12 09:35 AM, Philippe Gerum wrote:
>> On 01/16/2012 03:25 PM, Makarand Pradhan wrote:
>>> Hi,
>>>
>>> "Real-time pipes are deprecated."
>>>
>>> We use a lot of rt pipes. So, can you pl elaborate on this? I would
>>> highly appreciate if you can comment on the following.
>>>
>>> 1. When will the rt pipe interface be removed? Any time frame?
>> Xenomai 3. Xenomai 2.x will keep them forever.
>>
>>> 2. Would like to understand the reason for deprecating the interface.
>>>
>> - Because there is a better socket-based API implemented by the RTIPC
>> driver w/ the XDDP protocol, which does not require running application
>> level code in kernel space (RT_PIPE is definitely an application level
>> API). This new interface is available since Xenomai 2.5.x. It is
>> functionally 100% equivalent to the legacy RT_PIPE API.
>>
>> - Because no support will be provided in Xenomai 3 for running
>> application level code in kernel space, so RT_PIPE have to go from
>> kernel space. However, RT_PIPE are still part of the user-space API of
>> Xenomai 3, interfacing with XDDP endpoints in kernel space.
>>
>> I'm really referring to application level code, by contrast to RTDM
>> driver level code which will obviously remain a first-class citizen in
>> kernel space.
>>
>> See:
>>
>> o http://www.xenomai.org/index.php/Xenomai:Roadmap
>>
>> o
>> http://www.xenomai.org/documentation/xenomai-2.6/html/api/group__rtipc.html
>>
>>
>> o examples/rtdm/profiles/ipc in the Xenomai distro
>>
>>> Thanks and Rgds,
>>> Mak.
>>>
>>>
>>> On 15/01/12 12:37 PM, Gilles Chanteperdrix wrote:
>>>> Real-time pipes are deprecated.
>>>
>>
>
>


-- 
Philippe.

Re: [Xenomai-core] realtime pipes

[Makarand Pradhan]

Thanks.

On 16/01/12 10:24 AM, Philippe Gerum wrote:
> On 01/16/2012 04:09 PM, Makarand Pradhan wrote:
>> Thanks Philippe.
>>
>> To ensure that I understand correctly, let me rephrase my understanding.
>>
>> In 3.0, the rt_pipe_create and friends will cease to exist. We have to
>> start using the sockets with domain AF_RTIPC and protocol IPCPROTO_XDDP
>> instead.
>>
>> Is that a correct statement?
> Basically, yes. In addition, X3 will keep the RT_PIPE interface for the
> -rt endpoint available on the application-side, by wrapping a XDDP
> socket to a RT_PIPE descriptor under the hood. In kernel space however,
> the RT_PIPE API to create -rt endpoints won't be available anymore, one
> will have to create them via the rtdm_socket/rt_dev_socket calls.
>
> In any case, the API for the non-rt side does not change, i.e. POSIX
> file I/O calls will still be the way to interface with the -rt endpoint.
>
>> Rgds,
>> Mak.
>>
>> On 16/01/12 09:35 AM, Philippe Gerum wrote:
>>> On 01/16/2012 03:25 PM, Makarand Pradhan wrote:
>>>> Hi,
>>>>
>>>> "Real-time pipes are deprecated."
>>>>
>>>> We use a lot of rt pipes. So, can you pl elaborate on this? I would
>>>> highly appreciate if you can comment on the following.
>>>>
>>>> 1. When will the rt pipe interface be removed? Any time frame?
>>> Xenomai 3. Xenomai 2.x will keep them forever.
>>>
>>>> 2. Would like to understand the reason for deprecating the interface.
>>>>
>>> - Because there is a better socket-based API implemented by the RTIPC
>>> driver w/ the XDDP protocol, which does not require running application
>>> level code in kernel space (RT_PIPE is definitely an application level
>>> API). This new interface is available since Xenomai 2.5.x. It is
>>> functionally 100% equivalent to the legacy RT_PIPE API.
>>>
>>> - Because no support will be provided in Xenomai 3 for running
>>> application level code in kernel space, so RT_PIPE have to go from
>>> kernel space. However, RT_PIPE are still part of the user-space API of
>>> Xenomai 3, interfacing with XDDP endpoints in kernel space.
>>>
>>> I'm really referring to application level code, by contrast to RTDM
>>> driver level code which will obviously remain a first-class citizen in
>>> kernel space.
>>>
>>> See:
>>>
>>> o http://www.xenomai.org/index.php/Xenomai:Roadmap
>>>
>>> o
>>> http://www.xenomai.org/documentation/xenomai-2.6/html/api/group__rtipc.html
>>>
>>>
>>> o examples/rtdm/profiles/ipc in the Xenomai distro
>>>
>>>> Thanks and Rgds,
>>>> Mak.
>>>>
>>>>
>>>> On 15/01/12 12:37 PM, Gilles Chanteperdrix wrote:
>>>>> Real-time pipes are deprecated.
>>
>


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