diff --git a/examples/opt/executor.py b/examples/opt/executor.py
index 592a57b..3f3d23a 100644
--- a/examples/opt/executor.py
+++ b/examples/opt/executor.py
@@ -1,18 +1,19 @@
 import asyncio
 import time
+import torch
 from threading import Thread
-from typing import Any, Dict, Deque, List
+from typing import Any, Dict, Deque
 from collections import namedtuple, deque
 from energonai.logging import get_dist_logger
 
-GenerationArgs = namedtuple('GenerationArgs', ['top_k', 'top_p', 'temperature', 'max_tokens'])
-SubmitEntry = namedtuple('SubmitEntry', ['text', 'args'])
+GenerationArgs = namedtuple('GenerationArgs', ['top_k', 'top_p', 'temperature'])
+SubmitEntry = namedtuple('SubmitEntry', ['inputs', 'args', 'decode_steps'])
 
 
 class Executor:
-    def __init__(self, engine, tokenizer, max_batch_size: int = 1) -> None:
+    def __init__(self, engine, pad_token_id: int = 0, max_batch_size: int = 1) -> None:
         self.engine = engine
-        self.tokenizer = tokenizer
+        self.pad_token_id = pad_token_id
         self.max_batch_size = max_batch_size
         self.running: bool = False
         self.thread = None
@@ -24,12 +25,13 @@ def _start(self) -> None:
         self.running = True
         while self.running:
             if len(self.submit_queue) > 0:
-                inputs, entry_ids = self._make_batch()
+                inputs, entry_ids, trunc_lens, decode_steps = self._make_batch()
                 start = time.time()
                 outputs = self.engine.run(inputs).to_here()
-                for entry_id, output in zip(entry_ids, outputs):
-                    self.ready_map[entry_id] = self.tokenizer.decode(output, skip_special_tokens=True)
-                self.logger.info(f'batch size: {len(entry_ids)}, time: {time.time()-start:.3f} s')
+                for entry_id, output, trunc_len in zip(entry_ids, outputs, trunc_lens):
+                    self.ready_map[entry_id] = output[:trunc_len]
+                self.logger.info(
+                    f'batch size: {len(entry_ids)}, decode steps: {decode_steps}, time: {time.time()-start:.3f} s')
 
     def _make_batch(self):
         entry = self.submit_queue.popleft()
@@ -39,24 +41,31 @@ def _make_batch(self):
                 break
             if self.submit_queue[0].args != entry.args:
                 break
+            if self.submit_queue[0].decode_steps > entry.decode_steps:
+                break
             batch.append(self.submit_queue.popleft())
-        batch_text = [e.text for e in batch]
-        inputs = self.tokenizer(batch_text, padding=True, return_tensors='pt')
+        inputs, max_len = self._left_padding([e.inputs for e in batch])
+        entry_ids = []
+        trunc_lens = []
+        for e in batch:
+            entry_ids.append(id(e))
+            trunc_lens.append(max_len + e.decode_steps)
         inputs['top_k'] = entry.args.top_k
         inputs['top_p'] = entry.args.top_p
         inputs['temperature'] = entry.args.temperature
-        inputs['max_tokens'] = entry.args.max_tokens
-        return inputs, [id(e) for e in batch]
+        inputs['max_tokens'] = max_len + entry.decode_steps
+        return inputs, entry_ids, trunc_lens, entry.decode_steps
 
     def start(self):
         self.thread = Thread(target=self._start)
         self.thread.start()
 
-    def submit(self, promt, max_tokens, top_k, top_p, temperature):
+    def submit(self, inputs, max_tokens, top_k, top_p, temperature):
         if not self.running:
             raise RuntimeError('executor is shutdown')
-        args = GenerationArgs(top_k, top_p, temperature, max_tokens)
-        entry = SubmitEntry(promt, args)
+        args = GenerationArgs(top_k, top_p, temperature)
+        decode_steps = max_tokens - len(inputs['input_ids'])
+        entry = SubmitEntry(inputs, args, decode_steps)
         self.submit_queue.append(entry)
         return id(entry)
 
@@ -71,3 +80,17 @@ async def wait(self, entry_id):
     def teardown(self):
         self.running = False
         self.thread.join()
+
+    def _left_padding(self, batch_inputs):
+        max_len = max(len(inputs['input_ids']) for inputs in batch_inputs)
+        outputs = {'input_ids': [], 'attention_mask': []}
+        for inputs in batch_inputs:
+            input_ids, attention_mask = inputs['input_ids'], inputs['attention_mask']
+            padding_len = max_len - len(input_ids)
+            input_ids = [self.pad_token_id] * padding_len + input_ids
+            attention_mask = [0] * padding_len + attention_mask
+            outputs['input_ids'].append(input_ids)
+            outputs['attention_mask'].append(attention_mask)
+        for k in outputs:
+            outputs[k] = torch.tensor(outputs[k])
+        return outputs, max_len
diff --git a/examples/opt/opt_server.py b/examples/opt/opt_server.py
index c58e4a5..7afe696 100644
--- a/examples/opt/opt_server.py
+++ b/examples/opt/opt_server.py
@@ -24,8 +24,10 @@ class GenerationTaskReq(BaseModel):
 @app.post('/generation')
 async def generate(data: GenerationTaskReq, request: Request):
     logger.info(f'{request.client.host}:{request.client.port} - "{request.method} {request.url.path}" - {data}')
-    handle = executor.submit(data.prompt, data.max_tokens, data.top_k, data.top_p, data.temperature)
+    inputs = tokenizer(data.prompt)
+    handle = executor.submit(inputs, data.max_tokens, data.top_k, data.top_p, data.temperature)
     output = await executor.wait(handle)
+    output = tokenizer.decode(output, skip_special_tokens=True)
     return {'text': output}
 
 
@@ -83,7 +85,7 @@ def launch_engine(model_class,
                              port=port,
                              dtype=dtype)
     global executor
-    executor = Executor(engine, tokenizer, max_batch_size=16)
+    executor = Executor(engine, pad_token_id=tokenizer.pad_token_id, max_batch_size=16)
     executor.start()
 
     global server