CombinedLoader does not work in DDP when using max_size_cyle option

[ant0nsc]

🐛 Bug

When using a CombinedLoader with the max_size_cycle option and DDP, all the GPUs get all validation data.
This bug is related to #7013 - however, the fix in PR #7102 only affect the default min_size option of the CombinedLoader

@tchaton ?

To Reproduce

Repro

Expected behavior

For the above repro, the validation data has length 8. I would expect that each of the 2 GPUs only get 4 batches each, but in fact they get 8 batches.

Environment

• CUDA:
  - GPU:
  - Tesla K80
  - Tesla K80
  - available: True
  - version: 10.2
• Packages:
  - numpy: 1.21.2
  - pyTorch_debug: False
  - pyTorch_version: 1.8.0
  - pytorch-lightning: 1.5.0
  - tqdm: 4.62.3
• System:
  - OS: Linux
  - architecture:
  - 64bit
  -
  - processor: x86_64
  - python: 3.7.3
  - version: 18.04.1-Ubuntu SMP Wed Jul 28 23:14:18 UTC 2021

Additional context

[tchaton]

Dear @ant0nsc,

Thanks for raising this issue, it was in fact never supported. Currently looking into it.

Best,
T.C

[ant0nsc]

Thanks @tchaton ! is there a way how we can work around the issue in the meantime?

[tchaton]

Dear @ant0nsc,

I have a fix PR #10374. Would you mind trying it out?

Best,
T.C

[ant0nsc]

Wow, that was swift, thanks @tchaton ! I tried on my small repro, it works just fine now.