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Idea #22372

daqinterface - can it check, before start, for stale sharedmemory segments for the appropriate partition?

Added by Ron Rechenmacher 2 months ago. Updated 8 days ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
-
Target version:
-
Start date:
04/12/2019
Due date:
% Done:

0%

Estimated time:
Experiment:
-
Duration:

Description

Wondering if daqInterface can, before start when all processes are known to be down (i.e. valid shutdown), check for
stale shared memory segments?

History

#1 Updated by John Freeman 2 months ago

That would definitely be useful. The key there - no pun intended - is that DAQInterface would need to know what shared memory segments artdaq was planning to create given the set of processes about to be launched and the partition in question and then checking to see if those segments were already there. Not sure how straightforward that would be, but we can talk about it at the meeting on Monday.

#2 Updated by Eric Flumerfelt 2 months ago

I can certainly modify SharedMemoryEventManager so that the shared memory key at least reflects the partition number...probably 0xBE##PPPP and 0xCE##PPPP where ## represents the partition number and PPPP is the PID.

#3 Updated by Eric Flumerfelt 8 days ago

I have implemented this change to SMEM on artdaq:feature/22372_SMEM_PartitionNumberInKey. The keys will be 0xEE##PPPP for events and 0xBB##PPPP for broadcasts, where ## indicates the partition number and PPPP indicates the PID.



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