Support true 16-bit precision with deepspeed

[awaelchli]

What does this PR do?

Fixes Lightning-AI/lit-llama#216
Follow-up to recent half-precision support: #17287

cc @Borda @carmocca @awaelchli @justusschock

[github-actions]

⚡ Required checks status: All passing 🟢

Groups summary

🟢 pytorch_lightning: Tests workflow

Check ID	Status
pl-cpu (macOS-11, lightning, 3.8, 1.11)	success	✅
pl-cpu (macOS-11, lightning, 3.9, 1.12)	success	✅
pl-cpu (macOS-11, lightning, 3.10, 1.13)	success	✅
pl-cpu (macOS-11, lightning, 3.10, 2.0)	success	✅
pl-cpu (macOS-11, lightning, 3.8, 1.11, oldest)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.8, 1.11)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.9, 1.12)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.10, 1.13)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.10, 2.0)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.8, 1.11, oldest)	success	✅
pl-cpu (windows-2022, lightning, 3.8, 1.11)	success	✅
pl-cpu (windows-2022, lightning, 3.9, 1.12)	success	✅
pl-cpu (windows-2022, lightning, 3.10, 1.13)	success	✅
pl-cpu (windows-2022, lightning, 3.10, 2.0)	success	✅
pl-cpu (windows-2022, lightning, 3.8, 1.11, oldest)	success	✅
pl-cpu (macOS-11, pytorch, 3.8, 1.13)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.8, 1.13)	success	✅
pl-cpu (windows-2022, pytorch, 3.8, 1.13)	success	✅

These checks are required after the changes to src/lightning/fabric/plugins/precision/deepspeed.py, src/lightning/fabric/strategies/deepspeed.py.

🟢 pytorch_lightning: Azure GPU

Check ID	Status
pytorch-lightning (GPUs)	success	✅

These checks are required after the changes to src/lightning/fabric/plugins/precision/deepspeed.py, src/lightning/fabric/strategies/deepspeed.py.

🟢 fabric: Docs

Check ID	Status
make-doctest (fabric)	success	✅
make-html (fabric)	success	✅

These checks are required after the changes to src/lightning/fabric/plugins/precision/deepspeed.py, src/lightning/fabric/strategies/deepspeed.py.

🟢 lightning_fabric: CPU workflow

Check ID	Status
fabric-cpu (macOS-11, lightning, 3.8, 1.11)	success	✅
fabric-cpu (macOS-11, lightning, 3.9, 1.12)	success	✅
fabric-cpu (macOS-11, lightning, 3.10, 1.13)	success	✅
fabric-cpu (macOS-11, lightning, 3.10, 2.0)	success	✅
fabric-cpu (macOS-11, lightning, 3.8, 1.11, oldest)	success	✅
fabric-cpu (ubuntu-20.04, lightning, 3.8, 1.11)	success	✅
fabric-cpu (ubuntu-20.04, lightning, 3.9, 1.12)	success	✅
fabric-cpu (ubuntu-20.04, lightning, 3.10, 1.13)	success	✅
fabric-cpu (ubuntu-20.04, lightning, 3.10, 2.0)	success	✅
fabric-cpu (ubuntu-20.04, lightning, 3.8, 1.11, oldest)	success	✅
fabric-cpu (windows-2022, lightning, 3.8, 1.11)	success	✅
fabric-cpu (windows-2022, lightning, 3.9, 1.12)	success	✅
fabric-cpu (windows-2022, lightning, 3.10, 1.13)	success	✅
fabric-cpu (windows-2022, lightning, 3.10, 2.0)	success	✅
fabric-cpu (windows-2022, lightning, 3.8, 1.11, oldest)	success	✅
fabric-cpu (macOS-11, fabric, 3.8, 1.13)	success	✅
fabric-cpu (ubuntu-20.04, fabric, 3.8, 1.13)	success	✅
fabric-cpu (windows-2022, fabric, 3.8, 1.13)	success	✅

These checks are required after the changes to src/lightning/fabric/plugins/precision/deepspeed.py, src/lightning/fabric/strategies/deepspeed.py, tests/tests_fabric/plugins/precision/test_deepspeed.py, .github/workflows/ci-tests-fabric.yml.

🟢 lightning_fabric: Azure GPU

Check ID	Status
lightning-fabric (GPUs)	success	✅

These checks are required after the changes to src/lightning/fabric/plugins/precision/deepspeed.py, src/lightning/fabric/strategies/deepspeed.py, tests/tests_fabric/plugins/precision/test_deepspeed.py.

🟢 mypy

Check ID	Status
mypy	success	✅

These checks are required after the changes to src/lightning/fabric/plugins/precision/deepspeed.py, src/lightning/fabric/strategies/deepspeed.py.

🟢 install

Check ID	Status
install-pkg (ubuntu-22.04, app, 3.8)	success	✅
install-pkg (ubuntu-22.04, app, 3.10)	success	✅
install-pkg (ubuntu-22.04, fabric, 3.8)	success	✅
install-pkg (ubuntu-22.04, fabric, 3.10)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.8)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.10)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.8)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.10)	success	✅
install-pkg (ubuntu-22.04, notset, 3.8)	success	✅
install-pkg (ubuntu-22.04, notset, 3.10)	success	✅
install-pkg (macOS-12, app, 3.8)	success	✅
install-pkg (macOS-12, app, 3.10)	success	✅
install-pkg (macOS-12, fabric, 3.8)	success	✅
install-pkg (macOS-12, fabric, 3.10)	success	✅
install-pkg (macOS-12, pytorch, 3.8)	success	✅
install-pkg (macOS-12, pytorch, 3.10)	success	✅
install-pkg (macOS-12, lightning, 3.8)	success	✅
install-pkg (macOS-12, lightning, 3.10)	success	✅
install-pkg (macOS-12, notset, 3.8)	success	✅
install-pkg (macOS-12, notset, 3.10)	success	✅
install-pkg (windows-2022, app, 3.8)	success	✅
install-pkg (windows-2022, app, 3.10)	success	✅
install-pkg (windows-2022, fabric, 3.8)	success	✅
install-pkg (windows-2022, fabric, 3.10)	success	✅
install-pkg (windows-2022, pytorch, 3.8)	success	✅
install-pkg (windows-2022, pytorch, 3.10)	success	✅
install-pkg (windows-2022, lightning, 3.8)	success	✅
install-pkg (windows-2022, lightning, 3.10)	success	✅
install-pkg (windows-2022, notset, 3.8)	success	✅
install-pkg (windows-2022, notset, 3.10)	success	✅

These checks are required after the changes to src/lightning/fabric/plugins/precision/deepspeed.py, src/lightning/fabric/strategies/deepspeed.py.

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Thank you for your contribution! 💜

Note
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[justusschock]

Please add a changelog :)

[carmocca]

LGTM

Do you intend to port the feature to the Trainer too? If not, please create an issue to track the work

[awaelchli]

Yep! Created an issue #17609 to keep track.