[CPU] Fix NUMA/core binding for DP ranks (#32856)

python/sglang/srt/model_executor/model_runner.py

@@ -1415,8 +1415,14 @@ class ModelRunner:
         )
 
     def init_threads_binding(self):
+        # With --enable-dp-attention, dp partitions the existing TP group
+        # rather than spawning additional processes, so dp_size must not be
+        # multiplied into the process count here (unlike regular DP, where
+        # dp_size * tp_size * pp_size is the true worker count).
+        dp_size = 1 if get_parallel().enable_dp_attention else self.ps.dp_size
         self.local_omp_cpuid = numa_utils.init_threads_binding(
-            tp_rank=self.ps.tp_rank, tp_size=self.ps.tp_size
+            numa_index=self.gpu_id,
+            world_size=dp_size * self.ps.tp_size * self.ps.pp_size,
         )
 
     def apply_torch_tp(self):