Fix ZeRO 2 + Pipelining#677
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ShadenSmith merged 4 commits intodeepspeedai:masterfrom Jan 20, 2021
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leogao2
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RezaYazdaniAminabadi,
ShadenSmith,
arashashari,
awan-10,
cli99,
conglongli,
eltonzheng,
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This is great, thank you! |
ShadenSmith
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Jan 20, 2021
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Hi @leogao2 , looks like our auto-formatter wants to make some changes. Can you setup pre-commit with updated formatting? Thanks! |
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Merged, thanks @leogao2 ! |
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ZeRO 2 + Pipelining is broken. After hunting down the issue here (EleutherAI/gpt-neox#62), I've made a patch that seems to solve the issue but might create bad inefficiencies elsewhere.
Since this class turns
enable_backward_allreduceoff,self.overlapping_partition_gradients_reduce_epilogue()defined in theDeepSpeedEngineclass never actually runs. I suspect this is because of efficiency problems;get_flat_partitionin stage2.py might do something expensive memorywise (a quick glance at the code certainly gives off that impression); someone will have to look into that later. But in the meantime, this fixes ZeRO2 + Pipelining enough to run a demo.