fix: checkpoint saving with distributed optimizer + overlap param gather#949
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terrykong merged 1 commit intoNVIDIA-NeMo:mainfrom Aug 21, 2025
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… for checkpoint saving Signed-off-by: Ananth Subramaniam <ansubramania@nvidia.com>
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Thank you for the fix @ananthsub!
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…her (#949) Signed-off-by: Ananth Subramaniam <ansubramania@nvidia.com> Signed-off-by: Julien Veron Vialard <jveronvialar@nvidia.com>
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…her (NVIDIA-NeMo#949) Signed-off-by: Ananth Subramaniam <ansubramania@nvidia.com> Signed-off-by: Qidong Su <qidongs@nvidia.com>
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…her (NVIDIA-NeMo#949) Signed-off-by: Ananth Subramaniam <ansubramania@nvidia.com> Signed-off-by: Qidong Su <qidongs@nvidia.com>
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…her (NVIDIA-NeMo#949) Signed-off-by: Ananth Subramaniam <ansubramania@nvidia.com>
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What does this PR do ?
Fixes checkpoint saving when distributed optimizer + overlap param gather are used together. We need to disable/re-enable the pre-forward hooks around checkpoint saving as done here to force the parameter sync to ensure consistency before checkpoint saving: https://github.com/NVIDIA-NeMo/Megatron-Bridge/blob/742aaf84d9a3c4108b675968cc5b5ed59e4e4921/src/megatron/bridge/training/train.py#L787-L805
Currently state: the loss spikes on resume without this:
With this PR:
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