diff --git a/python/llm/src/ipex_llm/transformers/pipeline_parallel.py b/python/llm/src/ipex_llm/transformers/pipeline_parallel.py
index f292a80c..de5e5f56 100644
--- a/python/llm/src/ipex_llm/transformers/pipeline_parallel.py
+++ b/python/llm/src/ipex_llm/transformers/pipeline_parallel.py
@@ -509,14 +509,14 @@ class ModelRunner:
 
             return kv_cache_1
 
-    def update_kv_cache(self, kv_cache, cur_id):
+    def update_kv_cache(self, kv_cache, prefill=False):
         layer_start = self.model.layer_start
         layer_end = self.model.layer_end
         num_layers = self.model.num_layers
 
         if self.model.config.model_type == "chatglm" and self.model.config.num_layers == 40:
             # for glm-4-9b-chat
-            if self.past_key_values_dict.get(cur_id, None) is None:
+            if prefill:
                 value_placeholder = torch.empty_like((kv_cache)[-1][0])
                 past_key_values_placeholder = tuple(
                     (value_placeholder, value_placeholder) for _ in range(layer_start)
@@ -528,13 +528,10 @@ class ModelRunner:
                 pass
         elif self.model.config.model_type in ["baichuan", "chatglm"] and self.rank > 0:
             value_placeholder = torch.empty_like((kv_cache)[-1][0])
-            kv_cache = tuple((value_placeholder, value_placeholder)) + \
-                tuple(None for _ in range(layer_start)) + \
-                (kv_cache)[layer_start:]
-            # past_key_values_placeholder = tuple(
-            #     (value_placeholder, value_placeholder) for _ in range(layer_start)
-            # ) + (kv_cache)[layer_start:]
-            # kv_cache = past_key_values_placeholder
+            past_key_values_placeholder = tuple(
+                (value_placeholder, value_placeholder) for _ in range(layer_start)
+            ) + (kv_cache)[layer_start:]
+            kv_cache = past_key_values_placeholder
         else:
             pass
 
@@ -590,7 +587,7 @@ class ModelRunner:
                 # torch.xpu.empty_cache()
 
             if cur_batch.prefilled_index == cur_batch.batch_size:
-                tmp_past_key_values = self.update_kv_cache(tmp_past_key_values, cur_id)
+                tmp_past_key_values = self.update_kv_cache(tmp_past_key_values, True)
 
             self.past_key_values_dict[cur_id] = tmp_past_key_values
 
@@ -604,7 +601,8 @@ class ModelRunner:
                     _pre_output = torch.cat((_pre_output, tmp_output), dim=0)
                 self.partial_output_dict[cur_id] = _pre_output
         else:
-            _past_key_values = self.update_kv_cache(output.past_key_values, cur_id)
+            _prefill = self.past_key_values_dict.get(cur_id, None) is None
+            _past_key_values = self.update_kv_cache(output.past_key_values, prefill=_prefill)
             self.past_key_values_dict[cur_id] = _past_key_values
         torch.xpu.synchronize()
         if not self.pp_config.is_tail:
@@ -687,7 +685,6 @@ class ModelRunner:
 
             if (cur_batch is not None) and (not cur_batch.stopped) and (cur_input is None):
                 cur_id = cur_batch.batch_id
-                # cur_batch = self.prepare_batch(cur_batch)
                 if cur_batch.prefilled_index >= cur_batch.batch_size:
                     cur_batch.partial_prefilling = 0
                 if cur_batch.partial_prefilling > 0:
@@ -810,14 +807,9 @@ class ModelRunner:
                     dist.recv(cur_input, src=self.pre_rank)
 
         output, cur_batch = self.model_step(cur_input, cur_batch)
-        # if output is not None and self.rank == self.world_size - 1:
-        #     output = torch.argmax(output[:, -1:, :], dim=-1)
 
-        if output is not None:
-            # dist.send(output, dst=self.next_rank)
-            self.send_buff = output
-        else:
-            self.send_buff = None
+        self.send_buff = output
+
         if self.rank == 0:
             self.on_going_batches[:-1] = self.on_going_batches[1:]
             self.on_going_batches[self.world_size - 1] = cur_batch