From d26c9c8c3ba907b4d10f460974660b0174a19857 Mon Sep 17 00:00:00 2001
From: Jintao Huang <huangjintao.hjt@alibaba-inc.com>
Date: Thu, 9 Apr 2026 11:47:24 +0800
Subject: [PATCH] update get_parameter_local_cp

---
 .../model/modules/gated_delta_net.py          | 52 ++++++++++++++++++-
 1 file changed, 50 insertions(+), 2 deletions(-)

diff --git a/src/mcore_bridge/model/modules/gated_delta_net.py b/src/mcore_bridge/model/modules/gated_delta_net.py
index 8d0b4ea..93b129a 100644
--- a/src/mcore_bridge/model/modules/gated_delta_net.py
+++ b/src/mcore_bridge/model/modules/gated_delta_net.py
@@ -3,7 +3,7 @@
 import torch.nn.functional as F
 from megatron.core.inference.contexts import BaseInferenceContext
 from megatron.core.packed_seq_params import PackedSeqParams
-from typing import Optional
+from typing import List, Optional
 
 try:
     from fla.modules.convolution import causal_conv1d
@@ -21,6 +21,7 @@
     _GatedDeltaNet = object
 
 
+# Code borrowed from NVIDIA/Megatron-LM
 def _unpack_sequence(x, cu_seqlens, dim=1):
     unpacked_x = []
     num_seqs = cu_seqlens.shape[0] - 1
@@ -32,6 +33,53 @@ def _unpack_sequence(x, cu_seqlens, dim=1):
     return unpacked_x
 
 
+# Code borrowed from NVIDIA/Megatron-LM
+# Avoid the warning caused by `param[slices]`
+def get_parameter_local_cp(
+    param: torch.Tensor,
+    dim: int,
+    cp_group: torch.distributed.ProcessGroup,
+    split_sections: Optional[List[int]] = None,
+) -> torch.Tensor:
+    """Get the local parameter for the current context parallel rank.
+
+    Args:
+        param (torch.Tensor): The entire parameter to get the local parameter for.
+        dim (int): The dimension to split the parameter along. Usually the dimension of head.
+        cp_group (torch.distributed.ProcessGroup): The context parallel group.
+        split_sections (Optional[List[int]]): If not None,
+            first split the parameter along the dimension dim into sections,
+            then get the local hidden parallel weights separately,
+            finally concatenate the local hidden parallel weights along the dimension dim.
+
+    Returns:
+        torch.Tensor: The local parameter for the current context parallel rank.
+    """
+
+    cp_size = cp_group.size()
+    cp_rank = cp_group.rank()
+
+    # No need to split if CP size is 1.
+    if cp_size == 1:
+        return param
+
+    # Split first if needed.
+    if split_sections is not None:
+        inputs = torch.split(param, split_sections, dim=dim)
+        outputs = []
+        for p in inputs:
+            p = get_parameter_local_cp(p, dim, cp_group)
+            outputs.append(p)
+        return torch.cat(outputs, dim=dim)
+
+    # Slice the parameter.
+    slices = [slice(None)] * param.dim()
+    dim_size = param.size(dim=dim)
+    slices[dim] = slice(cp_rank * dim_size // cp_size, (cp_rank + 1) * dim_size // cp_size)
+    param = param[tuple(slices)]
+    return param
+
+
 class GatedDeltaNet(_GatedDeltaNet):
 
     def forward(
@@ -88,7 +136,7 @@ def forward(
         nvtx_range_pop(suffix='in_proj')
 
         if cp_size > 1:
-            from megatron.core.ssm.gated_delta_net import get_parameter_local_cp, tensor_a2a_cp2hp, tensor_a2a_hp2cp
+            from megatron.core.ssm.gated_delta_net import tensor_a2a_cp2hp, tensor_a2a_hp2cp
             if cu_seqlens is not None:
                 unpacked_qkvzba = _unpack_sequence(qkvzba, cu_seqlens // self.cp_size, dim=0)
                 outputs = []