[mpiwg-ft] FTWG Call Today

Wed Mar 15 12:46:55 CDT 2017

Hey Aurelien,

Thanks! I understand the concern.

For gloabal-restart models like Reinit (and I believe that for the SC14 
version of Fenix) this problem is solved by passing a reinit function 
pointer to MPI, which it then calls after initialization (this function 
is a replacement of main, and has the code that main originally 
contained). Since this reinit function is kept in the stack (it never 
returns), we can always long jump there.

I think the main problem is that we cannot long jump from a signal 
handler, or more specifically it is undefined according to the C 
language. We would need to find another mechanism for long jumping after 
a signal handler is called as a result of a failure notification.

Ignacio

On 3/15/17 8:41 AM, Aurelien Bouteiller wrote:
>
> Hey Ignacio,
>
> Murali wanted to touch with you on that exact issue. The bottom line is
> that a setjump must be in the same stack frame as the long jump, which
> means that you can jump only to a function in which you are nested in.
> In many cases that means you can’t “hide” set jumps points in the
> library, as they have to be called in the application function context
> (so that they remain in your frame).
>
> Best,
> Aurelien
>
>> On Mar 14, 2017, at 18:15, Ignacio Laguna <lagunaperalt1 at llnl.gov
>> <mailto:lagunaperalt1 at llnl.gov>> wrote:
>>
>> Thanks for sharing the minutes.
>>
>> In the "scoped reinit-like approaches", there is the point of "still
>> subject to the longjmp complication". Can folks comment on what is the
>> issue with respect to setjump/longjump in global-restart approaches,
>> such as Reinit and/or Fenix?
>>
>> Thanks!
>>
>> Ignacio
>>
>>
>> On 3/14/17 1:49 PM, Aurelien Bouteiller wrote:
>>> Minutes for the call have been posted here:
>>> https://github.com/mpiwg-ft/ft-issues/wiki/2017-03-14
>>>
>>>> On Mar 14, 2017, at 15:00, Aurelien Bouteiller <bouteill at icl.utk.edu
>>>> <mailto:bouteill at icl.utk.edu>
>>>> <mailto:bouteill at icl.utk.edu>> wrote:
>>>>
>>>> Hi there,
>>>>
>>>> Aurelien Bouteiller is inviting you to a scheduled Zoom meeting.
>>>>
>>>> Topic: MPI FT WG
>>>> Time: Mar 14, 2017 3:00 PM Eastern Time (US and Canada)
>>>>
>>>> Join from PC, Mac, Linux, iOS or
>>>> Android: https://tennessee.zoom.us/j/607816420?pwd=MuG6Nboy9%2Fo%3D
>>>>    Password: beef
>>>>
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>>>> +16465588656,607816420#
>>>>
>>>> Or Telephone:
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>>>>
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>>>>
>>>>
>>>>> On Mar 14, 2017, at 10:54, Aurelien Bouteiller
>>>>> <bouteill at icl.utk.edu <mailto:bouteill at icl.utk.edu>
>>>>> <mailto:bouteill at icl.utk.edu>> wrote:
>>>>>
>>>>> Hi all,
>>>>>
>>>>> We have the FTWG call scheduled for today. I’d like to debrief the
>>>>> latest MPI forum activities, and continue the discussion on
>>>>> converging localized and globalized recovery.
>>>>>
>>>>> I attach here the slide I used during the WG time.
>>>>> <20170228-mpiforum-errwg.pptx>
>>>>>
>>>>> We may also want to decide the time for our future meeting based on
>>>>> the doodle poll initiated by Wesley a while back.
>>>>> http://doodle.com/poll/s5uvmpux4nc6ki4y#table
>>>>>
>>>>> ===
>>>>> Looking back at the notes from our last call in December, I believe
>>>>> the TODO items are for Aurelien, Ignacio, and myself to flesh out the
>>>>> three FT recovery proposals and then see how they would interact with
>>>>> each other.
>>>>>
>>>>> * I believe Aurelien had some ideas about how to overcome some of the
>>>>> problems raised at the last meeting. Aurelien, if you could put
>>>>> together a slide or two that we could use for the discussion, that
>>>>> would probably be helpful.
>>>>> * I'm not sure of the status of Ignacio putting together some slides
>>>>> for the reinit proposal. If I remember the meeting long ago in San
>>>>> Jose, we just looked at a header. It might be nice to have something
>>>>> a little more high level to point to.
>>>>> * I still need to make the slides for the auto recovery strategy that
>>>>> Martin proposed.
>>>>>
>>>>> Once that's done, we can see where these things interact and how
>>>>> difficult it would be to support them together.
>>>>>
>>>>> Thoughts?
>>>>> Wesley
>>>>> _______________________________________________
>>>>> mpiwg-ft mailing list
>>>>> mpiwg-ft at lists.mpi-forum.org
>>>>> <mailto:mpiwg-ft at lists.mpi-forum.org> <mailto:mpiwg-ft at lists.mpi-forum.org>
>>>>> https://lists.mpi-forum.org/mailman/listinfo/mpiwg-ft
>>>>
>>>
>>>
>>>
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