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Subject: Re: [OMPI users] Tracing the library using gdb and xterm
From: Doug Reeder (dlr_at_[hidden])
Date: 2008-01-03 12:37:51


Krishna,

Would it work to launch the gdb/ddd process separately on the remote
machine and then attaching to the mpi running jobfrom within gdb/ddd.
Something like

ssh -X [hostname|ip address] [ddd|gdb]

Doug Reeder
On Jan 3, 2008, at 8:32 AM, Jeff Squyres wrote:

> Per my previous mail, Open MPI (by default) closes its ssh sessions
> after the remote processes are launched, so X forwarding through ssh
> will not work.
>
> If it is possible (and I think it is, based on your subsequent
> replies), you might be best served with unencrypted X forwarding.
>
>
> On Jan 3, 2008, at 11:02 AM, Doug Reeder wrote:
>
>> Krishna,
>>
>> Review the ssh and sshd man pages. When using ssh -X it takes care
>> of defining the DISPLAY and sending the X11 images to your screen.
>> Defining DISPLY directly generally won't work (that is how you do it
>> with rlogin but not with ssh).
>>
>> Doug Reeder
>> On Jan 3, 2008, at 1:54 AM, Krishna Chaitanya wrote:
>>
>>> Hi Rolf,
>>> Thanks for that. There is still one minor problem,
>>> though. The xwindow is getting spawned on the remote machine and
>>> not on my local machine. It now looks like,
>>> mpirun --prefix /usr/local -hostfile machines -x DISPLAY -x PATH -
>>> np 2 xterm -e gdb peruse_ex1
>>> Please let me know what i can do to have it displayed
>>> on my machine. I have the DISPLAY variable set to 0.0 on both the
>>> machines and I am ssh-ing into the other machine by using the -X
>>> switch.
>>>
>>> Thanks,
>>> Krishna Chaitanya
>>>
>>>
>>> On 1/2/08, Rolf Vandevaart <Rolf.Vandevaart_at_[hidden]> wrote: Krishna
>>> Chaitanya wrote:
>>>> Hi,
>>>> I have been tracing the interactions between the
>>> PERUSE
>>>> and MPI library,on one machine. I have been using gdb along with
>>> xterm
>>>> to have two windows open at the same time as I step through the
>>> code. I
>>>> wish to get a better glimpse of the working of the point to point
>>> calls,
>>>> by launching the job on two machines and by tracing the flow in a
>>>> similar manner. This is where I stand as of now :
>>>>
>>>> mpirun --prefix /usr/local -hostfile machines -np 2 xterm -e gdb
>>> peruse_ex1
>>>> xterm Xt error: Can't open display:
>>>> xterm: DISPLAY is not set
>>>>
>>>> I tried using the display option for xterm and
>>> setting
>>>> the value as 0.0, that was not of much help.
>>>> If someone can guide me as to where the DISPLAY
>>> parameter
>>>> has to be set to allow the remote machine to open the xterm
>>> window, it
>>>> will be of great help.
>>>>
>>>> Thanks,
>>>> Krishna
>>>>
>>>
>>> I also do the the following:
>>>
>>> -x DISPLAY -x PATH
>>>
>>> In this way, both your DISPLAY and PATH settings make it to the
>>> remote node.
>>>
>>> Rolf
>>> --
>>>
>>> =========================
>>> rolf.vandevaart_at_[hidden]
>>> 781-442-3043
>>> =========================
>>>
>>>
>>>
>>> --
>>> In the middle of difficulty, lies opportunity
>>> _______________________________________________
>>> users mailing list
>>> users_at_[hidden]
>>> http://www.open-mpi.org/mailman/listinfo.cgi/users
>>
>> _______________________________________________
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>
>
> --
> Jeff Squyres
> Cisco Systems
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