Skip to content

[PyTorch][CP] Add THD format support for AllGather-based Context Parallelism #2829

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
sudhakarsingh27 wants to merge 14 commits into
base: main
Choose a base branch
from
+365 −136
Open

[PyTorch][CP] Add THD format support for AllGather-based Context Parallelism #2829

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
14 commits
Select commit Hold shift + click to select a range
db44fc2
[PyTorch][CP] Fix THD AllGather CP: offset-based approach with proper…
sudhakarsingh27 Apr 7, 2026
1a5ca4c
[PyTorch][CP] Enable THD+all_gather tests in test_attention_with_cp
sudhakarsingh27 Apr 7, 2026
b4db9eb
[PyTorch][Fused Attn] Fix max_logit masking for non-zero-starting cu_…
sudhakarsingh27 Apr 7, 2026
7491ab6
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Apr 7, 2026
b957725
some cleanup of ag+thd impl and gate e e te test for flash+ag+thd
sudhakarsingh27 Apr 10, 2026
c89173c
Merge branch 'cp_thd_swa_with_ag' of github.com:sudhakarsingh27/Trans…
sudhakarsingh27 Apr 10, 2026
18e41bd
Merge branch 'main' of github.com:NVIDIA/TransformerEngine into cp_th…
sudhakarsingh27 Apr 10, 2026
0b48746
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Apr 10, 2026
608106d
improve the logic and remvoe for loop from the code
sudhakarsingh27 Apr 13, 2026
4b95130
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Apr 13, 2026
15af3af
Merge branch 'main' of github.com:NVIDIA/TransformerEngine into cp_th…
sudhakarsingh27 Apr 13, 2026
5bec5b3
Merge branch 'cp_thd_swa_with_ag' of github.com:sudhakarsingh27/Trans…
sudhakarsingh27 Apr 13, 2026
89b1066
AG+THD SWA: extend KV visibility for right window and rename a2a-spec…
sudhakarsingh27 Apr 16, 2026
55fc2cd
[pre-commit.ci] auto fixes from pre-commit.com hooks
pre-commit-ci[bot] Apr 16, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
7 changes: 4 additions & 3 deletions tests/pytorch/attention/test_attention_with_cp.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -100,7 +100,10 @@ def test_cp_with_flash_attention(dtype, model, qkv_format, cp_comm_type):
pytest.skip("CP implementation with KV all-gather does not support bias yet!")
if qkv_format == "thd":
if cp_comm_type == "all_gather":
pytest.skip("CP implementation with KV all-gather does not support THD format yet!")
pytest.skip(
"FlashAttention does not support THD padding; use FusedAttention for"
" THD+all_gather CP."
Copy link
Copy Markdown
Collaborator

@cyanguwa cyanguwa Apr 17, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Maybe swap the words a little bit so it doesn't sounds like FlashAttention doesn't support THD, but just our CP implementation with it doesn't? (Also, THD implies padding in our terminology?)

)
if cp_comm_type == "a2a+p2p":
pytest.skip(
"CP implementation with QKVO A2A+P2P (Hierarchical A2A) does not support THD format"
Expand Down Expand Up @@ -267,8 +270,6 @@ def test_cp_with_fused_attention(
if qkv_format == "thd" and config.attn_bias_type == "post_scale_bias":
pytest.skip("THD format does not support post_scale_bias yet!")
if qkv_format == "thd":
if cp_comm_type == "all_gather":
pytest.skip("CP implementation with KV all-gather does not support THD format yet!")
Copy link
Copy Markdown
Collaborator

@cyanguwa cyanguwa Apr 17, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

A general comment - please run the CP file with "test_essential=False" offline because the essential tests may not cover everything.

if cp_comm_type == "a2a+p2p":
pytest.skip(
"CP implementation with QKVO A2A+P2P (Hierarchical A2A) does not support THD format"
Expand Down
Loading
Loading