sgl-project--sglang/python/sglang/srt/layers/dcp/__init__.py

# Copyright 2023-2026 SGLang Team
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================

"""Decode Context Parallel (DCP) — consolidated home for the primitives that
were previously split between layers/attention/utils.py (PR #25090, Triton/MHA)
and layers/utils/dcp_utils.py (PR #14194, FlashInfer-MLA).

The two ``cp_lse_ag_out_rs`` variants are kept distinct (``_mha`` torch/all-reduce,
``_mla`` Triton/reduce-scatter) because their bodies are backend-forced.

Only the symbols imported by code OUTSIDE this subpackage are re-exported here.
Package-internal helpers (the @triton.jit kernels, ``CPTritonContext``,
``correct_attn_out``, ``create_dcp_kv_indices``, ``update_kv_lens_and_indices``,
``_all_gather_dcp_kv_cache``) stay private to their submodules — import them from
``sglang.srt.layers.dcp.{kernels,comm}`` if ever needed internally.

``dcp_enabled`` / ``get_attention_dcp_*`` remain compatibility exports for
out-of-tree callers; in-tree code should use ``get_parallel().dcp_enabled`` and
``get_parallel().attn_dcp_*``."""

from sglang.srt.layers.dcp.comm import (
    all_gather_kv_cache_for_dcp,
    all_gather_kv_cache_for_mha_chunk_extend,
    all_gather_kv_cache_for_mha_extend,
    all_gather_kv_cache_for_mla_extend,
    all_gather_q_for_mla_decode,
    cp_lse_ag_out_rs_mha,
    cp_lse_ag_out_rs_mla,
    dcp_enabled,
    get_attention_dcp_rank,
    get_attention_dcp_world_size,
)
from sglang.srt.layers.dcp.kernels import create_triton_kv_indices_for_dcp_triton
from sglang.srt.layers.dcp.layout import (
    filter_dcp_local_kv_indices,
    get_dcp_lens,
    update_local_kv_lens_for_dcp,
)
from sglang.srt.layers.dcp.metadata import DecodeContextParallelMetadata

# NOTE: planner.py is intentionally NOT imported here. It depends on server_args
# (get_server_args), whereas this package-init executes at module-load time
# for every eager importer of the DCP primitives — triton_backend,
# mem_cache.memory_pool, mem_cache.triton_ops.mla_buffer, mem_cache.kv_cache_builder,
# the FlashInfer-MLA / FlashMLA backends, and the deepseek forward methods. Keeping
# the init server_args-free avoids a load-time import edge into server_args. Import
# planner functions from sglang.srt.layers.dcp.planner directly.

__all__ = [
    "DecodeContextParallelMetadata",
    "all_gather_kv_cache_for_dcp",
    "all_gather_kv_cache_for_mha_chunk_extend",
    "all_gather_kv_cache_for_mha_extend",
    "all_gather_kv_cache_for_mla_extend",
    "all_gather_q_for_mla_decode",
    "cp_lse_ag_out_rs_mha",
    "cp_lse_ag_out_rs_mla",
    "create_triton_kv_indices_for_dcp_triton",
    "dcp_enabled",
    "filter_dcp_local_kv_indices",
    "get_attention_dcp_rank",
    "get_attention_dcp_world_size",
    "get_dcp_lens",
    "update_local_kv_lens_for_dcp",
]