Question about SingleFlow.prev in ring all-reduce
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- Python
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Description
In the first round of Ring All-Reduce, why is the prev field of SingleFlow set to the previous rank?
Isn't the first-round flow supposed to be initiated independently by each rank?
Why does it need a prev rank?
Code is in MockNcclGroup.cc: line 1168.
if(rank_it->second[0]!=-1){
prevranks={rank_it->second[0]};
}
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Research direction
Read MockNcclGroup.cc at line 1168 and trace SingleFlow.prev through the first ring all-reduce round. Compare the flow construction with the per-rank initiation described in the issue; done means documenting why prev is set and whether the implementation matches the intended behavior.
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Assessment
- Tech stack
- cpp
- Domain
- distributed-systems
- Issue type
- Documentation
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100