DTensor: avoid unnecessary DTensorSpec creation in _ToTorchTensor.backward#167588
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swolchok wants to merge 3 commits intogh/swolchok/868/basefrom
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DTensor: avoid unnecessary DTensorSpec creation in _ToTorchTensor.backward#167588swolchok wants to merge 3 commits intogh/swolchok/868/basefrom
swolchok wants to merge 3 commits intogh/swolchok/868/basefrom
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🔗 Helpful Links🧪 See artifacts and rendered test results at hud.pytorch.org/pr/167588
Note: Links to docs will display an error until the docs builds have been completed. ✅ You can merge normally! (1 Unrelated Failure)As of commit 035049e with merge base 573a79f ( UNSTABLE - The following job is marked as unstable, possibly due to flakiness on trunk:
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ezyang
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Nov 14, 2025
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Huh, I'm surprised this actual is an improvement lol
albanD
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Nov 14, 2025
| ): | ||
| # Avoid actual sharing of specs in case they're modified during (e.g.) | ||
| # sharding propagation. | ||
| grad_spec = copy.copy(dtensor_spec) |
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Is copying really that much faster?
copy in this case I would expect is actually doing a pickle serialization/deserialization of the object to get a new copy.
Is that really faster than creating a clean object below?
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Is that really faster than creating a clean object below?
Yes. DTensorSpec does some relatively expensive computation in its constructor
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@pytorchbot merge |
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Merge startedYour change will be merged once all checks pass (ETA 0-4 Hours). Learn more about merging in the wiki. Questions? Feedback? Please reach out to the PyTorch DevX Team |
jsuarez5341
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Nov 15, 2025
…kward (pytorch#167588) Looks like the check here is cheap and has a potentially large payoff. Pull Request resolved: pytorch#167588 Approved by: https://github.com/ezyang
Silv3S
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Nov 18, 2025
…kward (pytorch#167588) Looks like the check here is cheap and has a potentially large payoff. Pull Request resolved: pytorch#167588 Approved by: https://github.com/ezyang
pytorchmergebot
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Nov 21, 2025
``` git revert --no-commit 567dcdb 200156e 3d801a4 2034ca9 480b4ff f570e58 ``` And Revert "[DTensor] Document fast-path dispatch (#168192)" And Revert "[DTensor] Fix deadlock after fast cache clear (#168069)" Reverts: * #167860 * #167588 * #167475 * #166808 * #166372 * #168192 * #168069 Signed-off-by: Edward Z. Yang <ezyang@meta.com> Pull Request resolved: #168264 Approved by: https://github.com/seemethere, https://github.com/malfet
JacobSzwejbka
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Dec 8, 2025
``` git revert --no-commit 567dcdb 200156e 3d801a4 2034ca9 480b4ff f570e58 ``` And Revert "[DTensor] Document fast-path dispatch (#168192)" And Revert "[DTensor] Fix deadlock after fast cache clear (#168069)" Reverts: * #167860 * #167588 * #167475 * #166808 * #166372 * #168192 * #168069 Signed-off-by: Edward Z. Yang <ezyang@meta.com> Pull Request resolved: #168264 Approved by: https://github.com/seemethere, https://github.com/malfet
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Stack from ghstack (oldest at bottom):
Looks like the check here is cheap and has a potentially large payoff.
cc @H-Huang @awgu @wanchaol @fegin @fduwjj @wz337 @wconstab @d4l3k @pragupta @msaroufim @dcci