Fix https://github.com/pytorch/pytorch/issues/134095
This fix distributed state dict full_state_dict option hang during set_state_dict. We switch `_distribute_tensors` in _state_dict_utils.py to use `DTensor.from_local` instead of `distribute_tensor` to support FSDP2+TP 2D strided sharding use case, as `distribute_tensor` cannot handle strided sharding yet. `distribute_tensor` incurs a scatter behind the scenes, while `DTensor.from_local` takes the local slice from the full tensor on each rank to create the DTensor (no collective). This means it's the user's responsibility to make sure the full_tensor from the full_state_dict is the same across all ranks.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/135725
Approved by: https://github.com/fegin
Fix https://github.com/pytorch/pytorch/issues/134095
This fix distributed state dict full_state_dict option hang during set_state_dict. We switch `_distribute_tensors` in _state_dict_utils.py to use `DTensor.from_local` instead of `distribute_tensor` to support FSDP2+TP 2D strided sharding use case, as `distribute_tensor` cannot handle strided sharding yet. `distribute_tensor` incurs a scatter behind the scenes, while `DTensor.from_local` takes the local slice from the full tensor on each rank to create the DTensor (no collective). This means it's the user's responsibility to make sure the full_tensor from the full_state_dict is the same across all ranks.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/135725
Approved by: https://github.com/fegin
reland of https://github.com/pytorch/pytorch/pull/133113
I have to create a new PR because the previous reverted PR could not either be rebased, or imported successfully :(
----
Moving DTensor to be in the public namespace, to formally add the documentation page that includes all the public APIs. This includes:
* many path renames and path import fixes
* a dedicated doc page without too much content yet (adding in the next PRs)
* To preserve the BC for users still using the torch.distributed._tensor, I added a shim script to redirect old path calls to the new module
The BC preserving is evidented by the fact that all DTensor tests are still working without changing the public imports. So it's safe to land the changes
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134203
Approved by: https://github.com/tianyu-l
Optimize memory cost at [PR#129635](https://github.com/pytorch/pytorch/pull/129635)
There are 2 main part of the optimization here:
1. optimize the tensor distributing part, postpone the full_tensor generation, which avoids the memory overlap, saves around 50% peak memory at 2 param test case.
2. apply `assign=True` for the `load_state_dict`, saves memory cost at the state dict loading by assigning the input param, around 50% peak memory at loading part.
Future work:
Memory optimization to the opt will be conducted in the next PR
Pull Request resolved: https://github.com/pytorch/pytorch/pull/134025
Approved by: https://github.com/fegin
Co-authored-by: Rachel Guo <guorachel@meta.com>
Moving DTensor to be in the public namespace, to formally add the
documentation page that includes all the public APIs. This includes:
* many path renames and path import fixes
* a dedicated doc page without too much content yet (adding in the next
PRs)
* To preserve the BC for users still using the `torch.distributed._tensor`,
I added a shim script to redirect old path calls to the new module
The BC preserving is evidented by the fact that all DTensor tests are still
working without changing the public imports. So it's safe to land the
changes
Pull Request resolved: https://github.com/pytorch/pytorch/pull/133113
Approved by: https://github.com/XilunWu
ghstack dependencies: #133305, #133306
Causing some terrible error messages e.g. :
```
# printing directly: cudaError.???
# casting to int first: 712
Traceback (most recent call last):
File "/data/users/lpasqualin/fbsource/fbcode/scripts/lpasqualin/playground.py", line 15, in <module>
main()
File "/data/users/lpasqualin/fbsource/fbcode/scripts/lpasqualin/playground.py", line 11, in main
_create_cpu_state_dict(sd, share_memory=True, pin_memory=True)
File "/home/lpasqualin/pytorch/torch/distributed/_state_dict_utils.py", line 436, in _create_cpu_state_dict
ret = _iterate_state_dict(
^^^^^^^^^^^^^^^^^^^^
File "/home/lpasqualin/pytorch/torch/distributed/_state_dict_utils.py", line 143, in _iterate_state_dict
ret = {
^
File "/home/lpasqualin/pytorch/torch/distributed/_state_dict_utils.py", line 144, in <dictcomp>
key: _iterate_state_dict(
^^^^^^^^^^^^^^^^^^^^
File "/home/lpasqualin/pytorch/torch/distributed/_state_dict_utils.py", line 125, in _iterate_state_dict
ret = tensor_func(iter_object, pg, device, companion_obj)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/lpasqualin/pytorch/torch/distributed/_state_dict_utils.py", line 428, in tensor_func
succ == 0
AssertionError: Pinning shared memory failed with error-code: cudaError.???
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/132089
Approved by: https://github.com/Skylion007
When pin_memory and share_memory both are set to True in _create_cpu_state_dict, the memory is pinned using cudaHostRegister but is never unpinned. So, once tensor is created and freed, when a new tensor is created the caching allocator is allocating the same memory. This fails with below error.
```
obj = <[RuntimeError('CUDA error: part or all of the requested memory range is already mapped\nCUDA kernel errors might be a...pile with `TORCH_USE_CUDA_DSA` to enable device-side assertions.\n') raised in repr()] Tensor object at 0x7f0028a4d6c0> pg = None, device = None, _ = None
```
This PR fixes this by unregistering this memory on tensor free by attaching a hook.
This is easily reproducible with xlformers checkpointing unit tests and the fix is verified with the same.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131270
Approved by: https://github.com/LucasLLC
Fixes#126950
`ptd_state_dict` with `broadcast_from_rank0=False` might miss 2 condition checks in the `set_optimizer_state_dict`
Here we add another condition `full_state_dict=True` with corresponding tensor distribution without broadcasting if broadcast_from_rank0=False
Pull Request resolved: https://github.com/pytorch/pytorch/pull/128004
Approved by: https://github.com/fegin
I found that returning the copy is actually useful in situations where you might do something like:
```
ret = _copy_state_dict(obj, cache)
ret.update(some_other_values)
```
and would like `cache` not to change structure from `ret.update(some_other_values)`. Open to some notes here, not returning a copy might force the user to do some additional copies for this case.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123567
Approved by: https://github.com/wz337
**Summary**
This PR extend `_offload_state_dict_to_cpu` to accept a `cpu_offload_state_dict` argument. If `cpu_offload_state_dict` is not None, `_offload_state_dict_to_cpu` will use `copy_` to copy the GPU data to the CPU tensors. This allows users to pass a pin_memory or share_memory version of `cpu_offload_state_dict`.
This PR also adds `_create_cpu_state_dict` to allow users to easily create a pin_memory or share_memory cpu state_dict.
**Performance improvement**
```
# The micro-benchmark has a source state_dict with 150 tensors, and each tensor is 50MB.
# The micro-benchmark is run on a H100 machine with PCIe 5
cpu_state_dict_2 = _create_cpu_state_dict(state_dict, pin_memory=True)
cpu_state_dict_3 = _create_cpu_state_dict(state_dict, share_memory=True)
# GPU->CPU memory: 4.6556 seconds
cpu_state_dict = _offload_state_dict_to_cpu(state_dict)
# GPU->pin memory: 0.1566 seconds
_offload_state_dict_to_cpu(state_dict, cpu_offload_state_dict=cpu_state_dict_2)
# GPU->shared memory: 0.5509 seconds (variation is quite large)
_offload_state_dict_to_cpu(state_dict, cpu_offload_state_dict=cpu_state_dict_3)
# GPU->pin memory->shared memory: 0.2550 seconds
_offload_state_dict_to_cpu(state_dict, cpu_offload_state_dict=cpu_state_dict_2)
_offload_state_dict_to_cpu(cpu_state_dict_2, cpu_offload_state_dict=cpu_state_dict_3)
```
Differential Revision: [D54045845](https://our.internmc.facebook.com/intern/diff/D54045845/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120378
Approved by: https://github.com/LucasLLC
Summary:
This PR serves as a follow-up fix to address numerical correctness concerns identified in PR #118197, and we should only wait on `AsyncCollectiveTensor`.
Without the change, we occasionally ran into exception: `AttributeError("'Tensor' object has no attribute 'wait'")`
Test Plan:
**CI**:
Wait for the CI test
**Test with prod model**:
- Tested with models and no-longer ran into the exception after checkpoint loading.
Differential Revision: D53680406
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119716
Approved by: https://github.com/fegin, https://github.com/Skylion007, https://github.com/wz337
