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@Chao1Han Chao1Han commented Aug 4, 2025

Fixes #ISSUE_NUMBER

# shard_consumer(shards[remote_rank], remote_rank)

stage_size = 2
for stage in range(1, group_size, stage_size):
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for stage in range(1, stage_size):

pytorchmergebot and others added 29 commits August 21, 2025 08:13
…rdering collectives (pytorch#160113)"

This reverts commit 9d18bf0.

Reverted pytorch#160113 on behalf of https://github.com/huydhn due to Sorry for reverting your change, but lots of failures showing up after this lands ([comment](pytorch#160113 (comment)))
…torch#161084)"

This reverts commit cfdaaaa.

Reverted pytorch#161084 on behalf of https://github.com/huydhn due to My mistake in not checking for nvidia-smi availability ([comment](pytorch#161084 (comment)))
…0957)

**Summary**
When output dtype is fp8, oneDNN does not ensure intermediate results in the range of [-448, 448] before converting to fp8. So, we may get NaN in the output, which is a disaster for inference. This PR fixes this issue by clamping the intermediate results by oneDNN's post-op clip.

**Test plan**
```
pytest -sv test/quantization/core/test_quantized_op.py -k "q and fp8"
```

Pull Request resolved: pytorch#160957
Approved by: https://github.com/Valentine233, https://github.com/CaoE
…torch#161136)

expose the pointer so that we can create the `ncclConfig_t` object from pytorch and use it elsewhere. this is useful to control the nccl communicator parameters for multiple nccl communicators.

Pull Request resolved: pytorch#161136
Approved by: https://github.com/kwen2501
Fixes issue that exhibited a device side memory access fault due to incorrect tensor life management

Pull Request resolved: pytorch#154864
Approved by: https://github.com/jeffdaily

Co-authored-by: Jeff Daily <[email protected]>
…collectives (pytorch#160113)

1. Applying @eellison idea from pytorch#146562 (comment) for estimate_peak_memory:
```
    """
    Alternative version of estimate_peak_memory, that respects the fact,
    that every SchedulerNode has multiple phases:
    1. alloc ( outputs )
    2. run_kernel
    3. dealloc last_use buffers
    estimate_peak_memory collapses memory into one value: size_alloc - size_free
    While peak memory happens after alloc.

    Duplicating the code to not migrate all callsites at once,
    In future usages of estimate_peak_memory will migrate to this version.
    """
```

- Applying this in `reorder_communication_preserving_peak_memory` pass.

2. Buffers during reordering can change deallocation point, if candidate and group to swap both are users of the f_input_buf and group contains last_use_snode.

- Addressing this tracking the last_use_snode for each buffer and recomputing current memory respecting the change in size_free (group_node after reordering is not the last user of the buffer and its size_free -= buffer_size, while candidate becomes the last user and candidate.size_free += buffer_size).

4. Adding env var `PYTORCH_REORDER_COLLECTIVES_LIMIT` for ablation to limit number of collectives to reorder.

What is after this PR:

Iterative recomputation of memory estimations matches full memory estimations.

Active memory is not regressing a lot, but reserved memory is significantly regressed.

Investigation and fix of "reserved" memory will be in following PRs.

BASELINE (bucketing AG and RS): active: 32Gb reserved: 34Gb
```
[rank0]:[titan] 2025-08-11 11:28:36,798 - root - INFO - step:  1  loss: 12.2722  grad_norm:  4.2192  active_memory: 24.66GiB(25.96%)  reserved_memory: 25.38GiB(26.72%)  tps: 99  tflops: 5.71  mfu: 0.58%
[rank0]:[titan] 2025-08-11 11:28:38,640 - root - INFO - step:  2  loss: 13.1738  grad_norm: 50.5566  active_memory: 32.14GiB(33.83%)  reserved_memory: 34.21GiB(36.01%)  tps: 4,448  tflops: 257.63  mfu: 26.05%
[rank0]:[titan] 2025-08-11 11:28:40,029 - root - INFO - step:  3  loss: 15.6866  grad_norm: 80.0862  active_memory: 32.14GiB(33.83%)  reserved_memory: 34.21GiB(36.01%)  tps: 5,900  tflops: 341.72  mfu: 34.55%
[rank0]:[titan] 2025-08-11 11:28:41,423 - root - INFO - step:  4  loss: 13.4853  grad_norm:  7.8538  active_memory: 32.14GiB(33.83%)  reserved_memory: 34.21GiB(36.01%)  tps: 5,881  tflops: 340.57  mfu: 34.44%
[rank0]:[titan] 2025-08-11 11:28:42,820 - root - INFO - step:  5  loss: 16.1191  grad_norm: 53.2481  active_memory: 32.14GiB(33.83%)  reserved_memory: 34.21GiB(36.01%)  tps: 5,867  tflops: 339.77  mfu: 34.35%
```
REORDER: active: 32Gb reserved: 36Gb
```
[rank0]:[titan] 2025-08-11 11:34:32,772 - root - INFO - step:  1  loss: 12.2490  grad_norm:  4.1944  active_memory: 24.66GiB(25.96%)  reserved_memory: 26.81GiB(28.22%)  tps: 85  tflops: 4.90  mfu: 0.50%
[rank0]:[titan] 2025-08-11 11:34:35,329 - root - INFO - step:  2  loss: 13.1427  grad_norm: 39.5942  active_memory: 32.14GiB(33.83%)  reserved_memory: 36.40GiB(38.31%)  tps: 3,205  tflops: 185.61  mfu: 18.77%
[rank0]:[titan] 2025-08-11 11:34:36,770 - root - INFO - step:  3  loss: 14.6084  grad_norm: 51.0743  active_memory: 32.14GiB(33.83%)  reserved_memory: 36.40GiB(38.31%)  tps: 5,688  tflops: 329.44  mfu: 33.31%
[rank0]:[titan] 2025-08-11 11:34:38,197 - root - INFO - step:  4  loss: 13.6181  grad_norm:  8.1122  active_memory: 32.14GiB(33.83%)  reserved_memory: 36.40GiB(38.31%)  tps: 5,744  tflops: 332.68  mfu: 33.64%
[rank0]:[titan] 2025-08-11 11:34:39,821 - root - INFO - step:  5  loss: 15.8913  grad_norm: 59.8510  active_memory: 32.14GiB(33.83%)  reserved_memory: 36.40GiB(38.31%)  tps: 5,046  tflops: 292.22  mfu: 29.55%
```

REORDER + SINK_WAITS_ITERATIVE: active: 35Gb reserved: 41Gb
```
[rank0]:[titan] 2025-08-11 11:31:36,119 - root - INFO - step:  1  loss: 12.2646  grad_norm:  4.1282  active_memory: 27.60GiB(29.05%)  reserved_memory: 32.49GiB(34.20%)  tps: 173  tflops: 10.00  mfu: 1.01%
[rank0]:[titan] 2025-08-11 11:31:37,452 - root - INFO - step:  2  loss: 13.2353  grad_norm: 42.4234  active_memory: 35.08GiB(36.92%)  reserved_memory: 41.62GiB(43.80%)  tps: 6,152  tflops: 356.26  mfu: 36.02%
[rank0]:[titan] 2025-08-11 11:31:38,780 - root - INFO - step:  3  loss: 13.8205  grad_norm: 24.0156  active_memory: 35.08GiB(36.92%)  reserved_memory: 41.62GiB(43.80%)  tps: 6,169  tflops: 357.29  mfu: 36.13%
[rank0]:[titan] 2025-08-11 11:31:40,106 - root - INFO - step:  4  loss: 13.1033  grad_norm:  9.1167  active_memory: 35.08GiB(36.92%)  reserved_memory: 41.62GiB(43.80%)  tps: 6,183  tflops: 358.10  mfu: 36.21%
[rank0]:[titan] 2025-08-11 11:31:41,443 - root - INFO - step:  5  loss: 16.3530  grad_norm: 51.8118  active_memory: 35.08GiB(36.92%)  reserved_memory: 41.62GiB(43.80%)  tps: 6,130  tflops: 355.03  mfu: 35.90%
```

Differential Revision: [D79886535](https://our.internmc.facebook.com/intern/diff/D79886535)
Pull Request resolved: pytorch#160113
Approved by: https://github.com/wconstab, https://github.com/eellison

Co-authored-by: eellison <[email protected]>
…rdering collectives (pytorch#160113)"

This reverts commit 517d38d.

Reverted pytorch#160113 on behalf of https://github.com/IvanKobzarev due to Segment tree starts failing on trunk even ciflows/trunk passed on PR ([comment](pytorch#160113 (comment)))
…)"

This reverts commit febfc3e.

Reverted pytorch#160794 on behalf of https://github.com/seemethere due to This if failing internal tests, see D80671241 ([comment](pytorch#160794 (comment)))
Summary: Added a `_set_node_metadata_hook` which automatically adds node.meta["val"] to every new node that gets created under this context.

Test Plan:
` buck2 test //mtia/host_runtime/afg/tests:test_dynamic_shapes_advanced_ops`
https://www.internalfb.com/buck2/866439a2-2ba6-42d1-8e43-508d60456e2e

`buck2 test //mtia/host_runtime/afg/tests:test_dynamic_shapes_basic_ops`
https://www.internalfb.com/intern/testinfra/testrun/11540474149662857

Rollback Plan:

Differential Revision: D80579336

Pull Request resolved: pytorch#161019
Approved by: https://github.com/blaine-rister
…1084)

Fixes pytorch#160988.  The root cause can be found in the same issue.  This fix ensures that when reuse old wheel is on and `torchaudio` wheel is not there, the inductor test job can still rebuild the wheel it needs
Pull Request resolved: pytorch#161084
Approved by: https://github.com/malfet, https://github.com/zou3519
…ytorch#160902)

This adds a new function `bypass_package` and `CompilePackage.bypass_current_entry()`. This allows us to safely bypass if there are models with unserializable or incompatible parts. When we encounter something incompatible, we'll raise a bypass and ignore that particular code in DynamoCodeEntry.

Pull Request resolved: pytorch#160902
Approved by: https://github.com/zhxchen17
Summary: att - should be no-op

Test Plan:
buck2 test //caffe2/test/cpp/nativert:static_kernel_ops_tests
Tests finished: Pass 24. Fail 0. Fatal 0. Skip 0. Build failure 0

Rollback Plan:

Differential Revision: D80216488

Pull Request resolved: pytorch#161087
Approved by: https://github.com/georgiaphillips, https://github.com/henryoier
…ach operations (pytorch#161128)

Summary:
The `reserve()` method is used to pre-allocate memory for the result vector before adding elements to it. This is an optimization that makes sense for several reasons:

1. Performance improvement: By pre-allocating memory for the exact number of elements needed, it avoids multiple reallocations and memory copies that would occur as the vector grows dynamically.

2. Memory efficiency: It ensures that the vector allocates exactly the amount of memory needed, no more and no less, which is efficient when we know the final size in advance.

3. Reduced overhead: Each reallocation typically involves:
- Allocating a new, larger block of memory
- Copying all existing elements to the new location
- Destroying the old elements
- Deallocating the old memory block
- Consistent performance: Without reservation, vector growth typically follows a geometric progression (like 1, 2, 4, 8, 16...), which can lead to unpredictable performance spikes when reallocation occurs.

Test Plan:
OSS CI & tests

Rollback Plan:

Differential Revision: D80674453

Pull Request resolved: pytorch#161128
Approved by: https://github.com/Skylion007
…h#161039)

Summary: C++'s polymorphism and reusing components help us reduce the amount of bolierplate codes here.

Test Plan:
CI & tests

Rollback Plan:

Differential Revision: D80594353

Pull Request resolved: pytorch#161039
Approved by: https://github.com/janeyx99
Disable min/max macro on Windows.

Pull Request resolved: pytorch#161133
Approved by: https://github.com/angelayi
Changes:
1. change set `include_dirs` to append value.
2. add append `libraries_dirs` for level_zero.

Pull Request resolved: pytorch#161146
Approved by: https://github.com/angelayi
Fixes pytorch#161066

There is a size check here, which causes the error.
https://github.com/pytorch/pytorch/blob/8ce81bcee1da294a34af0a90dc16483055e8c5a4/aten/src/ATen/native/mps/operations/Pad.mm#L39-L40

If the argument `pad` is empty, it will return the cloned tensor on CPU.

https://github.com/pytorch/pytorch/blob/8ce81bcee1da294a34af0a90dc16483055e8c5a4/aten/src/ATen/native/PadNd.cpp#L43-L64

Therefore, this PR fixes the empty padding argument error by checking the size first and returning a cloned tensor immediately if the padding size is 0.

Pull Request resolved: pytorch#161149
Approved by: https://github.com/malfet
torch._inductor.virtualized.OpsValue objects instance does not have shape attribute. This breaks the fp8 test on ROCm. Add the OpsValue class in todo list.

Pull Request resolved: pytorch#161166
Approved by: https://github.com/jeffdaily
…ytorch#160660)

Summary: In the consolidate_safetensors_files_on_every_rank method, where we use multiple ranks to combine sharded safetensors files, if there are more ranks in the world size, than there are safetensors file to consolidate, then some ranks don't have to do any work. When I had tested, this case wasn't caught, and there was an extra barrier call, causing issues for the ranks that had no work to do. They should wait at the end, as do the ranks with work.

Test Plan:
tested this case on a job e2e
added a unit test

Rollback Plan:

Differential Revision: D80273616

Pull Request resolved: pytorch#160660
Approved by: https://github.com/sibuachu
…orch#161145)

Combine multiple profiles into one:
```
python profile_analysis.py --combine <file1> <file2> ... <out>
```
This only works well if they have different pids, like from different programs in a distributed run.

<img width="1521" height="465" alt="combining_multiple_profiles" src="https://github.com/user-attachments/assets/aba7112b-e9a9-4075-b82b-a4e4408384da" />

Pull Request resolved: pytorch#161145
Approved by: https://github.com/xmfan
setup vllm test logics.
1.  install wheels generated from previous build stage
2. generate and install vllm test pkg list on run time based on the torch wheels in the instance
3. run test based on the pre-defined test plan

notice the test-plan format is temporary for some basic vllm testing
Pull Request resolved: pytorch#160361
Approved by: https://github.com/atalman, https://github.com/huydhn
…orch#160482)

Previously, DTensor kept its own copy of the generator state after the
first time a random operator was called on a DTensor. This copy would
evolve independently from the generator outside of DTensor.

After adding support for users to pass a specific generator into
random operators (e.g. `uniform_(..., generator=)`), it was determined
(in discussion on pytorch#159991) to change the semantics so that any random
operations performed on DTensor would evolve the state of the publicly
visible generators (either the default one or user-passed one).

The upsides are (1) it is now possible to call torch.manual_seed() at
any point in the program and have a consistent effect on DTensor, (2)
DTensor ops have an observable effect on the generator.  The downside is
that users are now responsible for seeding their generator before using
DTensor, ensuring all ranks use the same seed.

Fixes pytorch#159991

confirmed docs rendered OK

<img width="897" height="414" alt="image" src="https://github.com/user-attachments/assets/c082f0f0-5447-47aa-834f-65342eb237cd" />

Pull Request resolved: pytorch#160482
Approved by: https://github.com/wanchaol
Update outer reduction heuristics for significant speedups.

HuggingFace:
<img width="572" height="705" alt="Screenshot 2025-08-20 at 12 44 51 AM" src="https://github.com/user-attachments/assets/4872a23b-d136-423a-b2e6-187895bccba1" />

Average ~20% speedup on a kernel by kernel basis

TorchBench:
<img width="572" height="705" alt="Screenshot 2025-08-20 at 12 45 10 AM" src="https://github.com/user-attachments/assets/b8357b6d-6107-4104-b906-292a17d14d48" />

Average ~40% speedup on a kernel by kernel basis

<img width="1705" height="729" alt="Screenshot 2025-08-21 at 5 50 32 PM" src="https://github.com/user-attachments/assets/a9715a2b-9e6c-4b33-ba9f-7870dc561e31" />

Differential Revision: [D80630416](https://our.internmc.facebook.com/intern/diff/D80630416)
Pull Request resolved: pytorch#159093
Approved by: https://github.com/jansel
…orch#161201)

By changing dtype to float if device is MPS

Note: for some reason test runs much longer on MPS than on CPU
```
% python ../test/test_indexing.py -v -k test_index_put_accumulate_duplicate_indices_mps
test_index_put_accumulate_duplicate_indices_mps (__main__.TestIndexingMPS.test_index_put_accumulate_duplicate_indices_mps) ... ok

----------------------------------------------------------------------
Ran 1 test in 9.139s

OK
```
Pull Request resolved: pytorch#161201
Approved by: https://github.com/dcci
…addmm (pytorch#155357)"

This reverts commit ce048de.

Reverted pytorch#155357 on behalf of https://github.com/seemethere due to This is causing buck builds to fail since we didn't add the definition of AT_USE_EIGEN_SPARSE in the buckbuild.bzl file, will follow-up and re-land this. ([comment](pytorch#155357 (comment)))
Bumps [uv](https://github.com/astral-sh/uv) from 0.8.4 to 0.8.6.
- [Release notes](https://github.com/astral-sh/uv/releases)
- [Changelog](https://github.com/astral-sh/uv/blob/main/CHANGELOG.md)
- [Commits](astral-sh/uv@0.8.4...0.8.6)

---
updated-dependencies:
- dependency-name: uv
  dependency-version: 0.8.6
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
…ch#160205)

Parallelize reading of data behind thread_count argument to HFStorageReader
Test plan: ensure existing tests pass and run a job successfully with these changes

Differential Revision: [D79478188](https://our.internmc.facebook.com/intern/diff/D79478188/)

Pull Request resolved: pytorch#160205
Approved by: https://github.com/meetv18
Summary: att - changed one of the tests to get rid of torcharrow dep.

Test Plan:
```
buck2 test //caffe2/test/cpp/nativert:layout_planner_tests
Tests finished: Pass 15. Fail 0. Fatal 0. Skip 0. Build failure 0
```

Rollback Plan:

Reviewed By: SherlockNoMad

Differential Revision: D80108549

Pull Request resolved: pytorch#160942
Approved by: https://github.com/georgiaphillips, https://github.com/henryoier
justinchuby and others added 27 commits August 23, 2025 02:42
This PR is auto-generated nightly by [this action](https://github.com/pytorch/pytorch/blob/main/.github/workflows/nightly.yml).
Update the pinned vllm hash.
Pull Request resolved: pytorch#161227
Approved by: https://github.com/pytorchbot
After we switched to constructing the registry with the specified opset version in dynamo=True, support for opset<18 was broken because there would be no torchlib ops registered for these opsets. I updated the registry creation logic to always use opset 18 if the requested opset is lower, and use the version converter (as designed) to target those opsets.

This requires onnxscript>=0.4 (pytorch#161312)

Fixes onnx/onnx#7235

Pull Request resolved: pytorch#161056
Approved by: https://github.com/titaiwangms
Enable more vllm test against pytorch main, add schedule to run the test every 12 hours.

Pull Request resolved: pytorch#161192
Approved by: https://github.com/huydhn
…torch#161170)

Users encountered unexpected behaviour when using FlexAttention with learnable biases, including assertion errors (pytorch#157677)

We traced the root cause to the registration of subgraph buffers—this caused inconsistencies in the naming and ultimately incorrect retrieval later on. This problem only arose if the model was compiled as a whole (ie using @torch.compile) since only then would there be naming conflicts.

In this PR, we register the buffers with the base graph to solve this issue.

Pull Request resolved: pytorch#161170
Approved by: https://github.com/drisspg
…ytorch#160919)

Summary:
[The diff was reverted due to CLA error, in the process of retrieving account]
Previous error message
```
RuntimeError: Expected input at *args.<unknown location>.shape[0] to be equal to 4096, but got 7680. If you meant for this dimension to be dynamic, please re-export and specify dynamic_shapes (e.g. with Dim.DYNAMIC)
```
New error message
```
RuntimeError: Expected input at *args.[0].supervision_input.weight.shape[0] to be equal to 4096, but got 7680. If you meant for this dimension to be dynamic, please re-export and specify dynamic_shapes (e.g. with Dim.DYNAMIC)
```

Test Plan:
```
buck test mode/opt apf/rec/ir/tests:ir_export_deserialize_test
```
https://www.internalfb.com/intern/testinfra/testrun/4785074906254375

```
buck run mode/opt caffe2/test:test_export -- -r unflatten
```

```
Ran 413 tests in 208.414s

OK (skipped=1, expected failures=13)
```

Rollback Plan:

Differential Revision: D80487367

Pull Request resolved: pytorch#160919
Approved by: https://github.com/angelayi
Summary: AMD specific kwargs need to be removed from the guard, otherwise a keyerror will be raised when executing the kernel.

Test Plan:
```
buck2 run mode/opt-amd-gpu -m rocm641 -c fbcode.split-dwarf=true -c fbcode.use_link_groups=true -c fbcode.enable_gpu_sections=true //hpc/new/models/feed/benchmark:feed_lower_benchmark -- --load=manifold://ads_storage_fblearner/tree/user/facebook/fblearner/predictor/894698382/0/gpu_lowering/new_input8 --skip-eager --skip-flop-estimation --sync-mode=0 --lower-backend=AOT_INDUCTOR
```
can succeed after this change.

Rollback Plan:

Differential Revision: D80285441

Pull Request resolved: pytorch#160671
Approved by: https://github.com/muchulee8
# Context
In pytorch#160163, we added support for NUMA binding for `Callable` entrypoints to `elastic_launch`. This requires special consideration, because they go through a different path to spawn subprocesses compared to `str` entrypoints, a path which does not provide a straightforward way to utilize `numactl` CLI. See pytorch#160006 for a full description of the challenges.

Although pytorch#160163 worked in initial local experiments, we ran into some linker errors in other environments when we tried to call `numactl`. This appeared to be due to interactions with how the `LD_PRELOAD` environment variable was being set.

# This PR
On further thought, the most straightforward, foolproof solution here is to use [the trick that @d4l3k suggested.](pytorch#160006 (comment))

Specifically, for each local rank `i`:
1. The parent process sets its own CPU affinity to what local rank `i`'s should be.
2. Then, the parent spawns the subprocess for local rank `i`.
3. Finally, the parent resets its own CPU affinity to what it was originally.

There were other solutions that would work just for `Callable` entrypoints, but I believe this is the simplest one that can work for *both* `str` and `Callable`, and it's pretty simple.

This required a bit of refactoring:
1. Turn all the `_get_.*_numactl_options` into functions which return a set of logical CPUs to bind to, rather than options like `--cpunodebind=0`.
2. Instead of wrapping commands with `numactl`, use `os.sched_setaffinity` to bind to the CPUs from (1.).
3. Put this all inside a context manager which encapsulates applying and restoring the bindings in the parent process.
4. Use the context manager for both `str` and `Callable` paths

# Test Plan
## Automated
`$ pytest test/test_numa_binding.py`

## Manual
See [doc.](https://docs.google.com/document/d/1vxD-OKYBTT27jbBwtW9iz9g0tNM0u-i0tiTJg_ieQA8/edit?tab=t.0) Meta only, but TLDR tried out every combination of `str`, `Callable`, binding disabled, and binding enabled on the same model and saw 2x SM utilization for binding enabled.

Pull Request resolved: pytorch#161183
Approved by: https://github.com/d4l3k
…1182)"

This reverts commit e20f6d7.

Reverted pytorch#161182 on behalf of https://github.com/zou3519 due to broke dynamo_wrapped tests, those are a bit finicky to fix (there is probably more than one failure!) ([comment](pytorch#161182 (comment)))
By passing strides to strided variant of the tensor

Fixes pytorch#160993
Pull Request resolved: pytorch#161333
Approved by: https://github.com/huydhn, https://github.com/wdvr
ghstack dependencies: pytorch#161206, pytorch#161267
…ytorch#155357)

This pull request adds the following ops for sparse matrices using Eigen library:
```python
    add(a_csr, b_csr)
    add(a_csc, b_csc)

    addmm(c_csr, a_csr, b_csr)
    addmm(c_csr, a_csr, b_csc)
    addmm(c_csr, a_csc, b_csc)
    addmm(c_csr, a_csc, b_csr)

    addmm(c_csc, a_csr, b_csr)
    addmm(c_csc, a_csr, b_csc)
    addmm(c_csc, a_csc, b_csc)
    addmm(c_csc, a_csc, b_csr)
```

Currently, the operations for sparse matrices on CPU are available through MKL only. The non-existence of MKL on `aarch64` causes the unavailability of these ops on any machines with ARM based CPUs, including Apple Silicon, AWS Graviton and NVIDIA Grace. This PR addresses this issue by using Eigen as a backend for the above ops.

This is a re-factored version of my previous PR pytorch#101814. The main difference with the old one, this does not enable Eigen by default.
Pull Request resolved: pytorch#155357
Approved by: https://github.com/pearu, https://github.com/eqy

Co-authored-by: Eli Uriegas <[email protected]>
…ytorch#161316)

pytorch#159779

CUDA 13 added the support for --compress-mode flag for nvcc across all drivers of CUDA 13.X toolkits, enabling the possibility to use --compress-mode=size for significant size reduction (~71% less for CUDA Math APIs for example). https://developer.nvidia.com/blog/whats-new-and-important-in-cuda-toolkit-13-0/

Why we have to add for CUDA 13 only, quote from @ptrblck : Any usage of --compress-mode=size/balance will drop the support of older CUDA drivers and will bump the min. driver requirement to CUDA 12.4. pytorch#157791 (comment)

Default for CUDA 13 will be --compress-mode=balance which gives smaller binaries than LZ4 speed mode used in previous CUDA versions.

Related - pytorch#157791

Pull Request resolved: pytorch#161316
Approved by: https://github.com/nWEIdia, https://github.com/Skylion007
A single-device version of Muon. Algorithm refers Keller Jordan's [Muon blogpost](https://kellerjordan.github.io/posts/muon/), and optionally incorporates [Moonshot's](https://github.com/MoonshotAI/Moonlight/blob/master/Moonlight.pdf) learning rate adjustment strategy.

This implementation maintains a minimalist API and is consistent with other optimizer conventions. PyTorch team prefers to handle parameter filtering at a higher level, with the Muon optimizer performing only the msign computation for orthogonalization on all parameters it receives. Users are responsible for grouping parameters for different optimizers as needed. An example usage is shown below, and a more detailed example will be added to the [PyTorch examples](https://github.com/pytorch/examples) directory.

**Usage**

```python
    model = MyModelForCausalLM
    # filter out your params manually
    muon_params = [...]
    adamw_params = [...]
    muon = Muon(
        params = muon_params
        lr=lr,
        wd=wd,
    )
    adamw = AdamW(
        params = adamw_params
        lr=lr,
        wd=wd,
    )

    # in training loop
    loss = model(input)
    loss.backward()
    muon.step()
    adamw.step()
    muon.zero_grad()
    adamw.zero_grad()
```

~~**Additional usage**~~
~~Users are also able to pass in self-defined `msign` function for orthogonalization, and learning rate adjustment function. Interface defined below:~~

```python
~~AdjustLrFn: TypeAlias = Callable[[float, torch.Size], float]~~
~~MsignFn: TypeAlias = Callable[[Tensor, BaseMsignFnConfig], Tensor]~~
```

As discussed with team and in comment, we prefer to make the interface simpler and cleaner, thus we removed the callback interface, and canonicalize the original NS algorithm for Muon. The only configs available to users are `ns_steps`, `coefficients`, and `eps`, configurable through kwargs.

By default, we use 5-step Newton-Schulz, with coefficients proposed by [Keller](https://kellerjordan.github.io/posts/muon/). We use LR adjustment proposed by [Moonshot](https://github.com/MoonshotAI/Moonlight/blob/master/Moonlight.pdf), which grafts learning rate from AdamW.

**Testing**

~~1. Unit tests: the newly introduced Muon is covered in `test/test_optim.py`. We updated the test cases to pass named parameters to the optimizer under test. Additionally, we introduced a new test case to verify that when the user provides an empty FQN list, Muon correctly falls back to AdamW behavior.~~

As discussed, in order not to complicate the codebase, we prefer not to include reference implementation into PyTorch. We also updated the interface so we don't need to test the FQN based filtering. Muon is covered by the existing `test_optim.py` unit test.

2. End-to-end test: we added a training script that pre-trains a QWEN-like model on `openwebtext-100k` dataset. We trained for one epoch and the resulting loss curve is compared against the Moonshot implementation to confirm behavioral consistency.
<img width="1102" height="472" alt="Screenshot 2025-07-29 at 1 04 12 AM" src="https://github.com/user-attachments/assets/ceab0733-497d-4070-8032-02ae7995c64c" />

**Numerics**
We evaluate our implementation with existing implementation to confirm numerical consistency.

As discussed, our implementation closely follows the algorithm described in [Keller's post](https://kellerjordan.github.io/posts/muon/), while incorporating the learning rate adjustment from [Moonlight](https://github.com/MoonshotAI/Moonlight/blob/master/Moonlight.pdf). This captures a key insight that allows users to reuse hyper-parameters tuned for `adamW`, making Muon a drop-in swap.

As expected, the numerics difference mainly comes from `adjust_lr`, a max of ~5% relative diff in an example unit test setup below.

```python
    # dummy model and data
    model0 = Linear(10, 10, bias=False)
    model1 = copy.deepcopy(model0)
    inputs = torch.randn(8, 10)
    targets = torch.randn(8, 10)
    loss = MSELoss()

    lr = 1e-3
    wd = 0.1
    momentum = 0.95

    opt_ref_muon = KellySingleDeviceMuon(
        params=model0.parameters(),
        lr=lr,
        weight_decay=wd,
        momentum=momentum,
    )

    opt_exp_muon = Muon(
        params=model1.parameters(),
        lr=lr,
        weight_decay=wd,
        momentum=momentum,
    )

    out_ref = model0(inputs)
    loss_ref = loss(out_ref, targets)
    opt_ref_muon.zero_grad()
    loss_ref.backward()
    opt_ref_muon.step()

    out_exp = model1(inputs)
    loss_exp = loss(out_exp, targets)
    opt_exp_muon.zero_grad()
    loss_exp.backward()
    opt_exp_muon.step()

    for p_ref, p_exp in zip(model0.parameters(), model1.parameters()):
        torch.testing.assert_close(p_ref, p_exp)
```

As explained above, including this `adjust_lr` is preferable. This is validated by an e2e training runs on training a qwen-2-like 0.5b model, where the curves show that training with `adjust_lr` converges more effectively than without.
<img width="1179" height="464" alt="Screenshot 2025-08-18 at 10 12 33 AM" src="https://github.com/user-attachments/assets/e797d3da-c2f0-4187-b99e-5d48b7437c3c" />

**Performance**
Training for one epoch of openwebtext-100k on eight H100 GPUs with DDP:

- adamw_ddp finishes in 13.12 min
- pytorch_muon_ddp finishes in 13.45 min

Muon runs ~20s slower compared to AdamW. Assuming no other changes, Muon is *2.5%* slower than AdamW.

AdamW: Optimizer.step() takes ~13.5 ms, step time ~930 ms
<img width="726" height="590" alt="Screenshot 2025-07-29 at 1 56 14 AM" src="https://github.com/user-attachments/assets/ebcd7e1c-d129-4b20-9396-39f568edf03d" />

Muon: Optimizer.step() takes ~54 ms, step time ~960 ms
<img width="751" height="597" alt="Screenshot 2025-07-29 at 2 02 20 AM" src="https://github.com/user-attachments/assets/72f5b904-ebd5-4502-a6ff-d3e9e5a6da81" />

**Note**
We restrict the implementation to accept only 2D parameters.

An alternative approach is to allow parameters with more than two dimensions and apply orthogonalization over the last two dimensions. We opt not to go with this approach as it can be error-prone. For example, with a kernel shaped `[in_channel, height, width, out_channel]`, applying orthogonalization to the last two dimensions is not meaningful.

Since Muon is designed to operate orthogonalization on 2D matrices, preserving this assumption keeps the implementation clean and sound.

**Next Steps**

1. Add `MuP`
2. Open-source optimized triton kernel for symmetric matmul. A preliminary benchmark found 1.23x - 1.48x speedup on small - large (n = 256 -> 16384) matrices.
3. Open-source unsharded Muon co-designed with FSDP2.

****

Pull Request resolved: pytorch#160213
Approved by: https://github.com/janeyx99
…orch#160482)

Previously, DTensor kept its own copy of the generator state after the
first time a random operator was called on a DTensor. This copy would
evolve independently from the generator outside of DTensor.

After adding support for users to pass a specific generator into
random operators (e.g. `uniform_(..., generator=)`), it was determined
(in discussion on pytorch#159991) to change the semantics so that any random
operations performed on DTensor would evolve the state of the publicly
visible generators (either the default one or user-passed one).

The upsides are (1) it is now possible to call torch.manual_seed() at
any point in the program and have a consistent effect on DTensor, (2)
DTensor ops have an observable effect on the generator.  The downside is
that users are now responsible for seeding their generator before using
DTensor, ensuring all ranks use the same seed.

Fixes pytorch#159991

confirmed docs rendered OK

<img width="897" height="414" alt="image" src="https://github.com/user-attachments/assets/c082f0f0-5447-47aa-834f-65342eb237cd" />

Pull Request resolved: pytorch#160482
Approved by: https://github.com/wanchaol
In this PR we will port all distributed pipeline test files.
We could enable Intel GPU with following methods and try the best to keep the original code styles:

1. instantiate_device_type_tests()
2. use "torch.accelerator.current_accelerator()" to determine the accelerator backend
3. use "requires_accelerator_dist_backend()" to replace requires_nccl()
4. use "get_default_backend_for_device()" to get backend
5. enabled XPU for some test path

Pull Request resolved: pytorch#159033
Approved by: https://github.com/guangyey, https://github.com/kwen2501
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