Add profile (#15)

* remove constraints on model name

* remove duplicate model converter

* add profile

* get eos and bos from server

* update stop_words

* update sequence_length when the last generated token is eos_id

* fix

* fix

* check-in models

* valicate model_name

* make stop_words as property

* debug profiling

* better stats

* fix assistant reponse

* update profile serving

* update

* update

benchmark/profile_generation.py

+import multiprocessing as mp
+import time
+
+import fire
+import numpy as np
+
+from llmdeploy.serve.fastertransformer.chatbot import Chatbot
+
+
+def infer(chatbot, session_id: int, prompt: str, output_seqlen: int,
+          test_round: int, que: mp.Queue):
+    stats = []
+    for i in range(test_round):
+        timestamps = []
+        tokens = []
+        start = time.perf_counter()
+        for status, res, token in chatbot.stream_infer(
+                session_id,
+                prompt,
+                request_output_len=output_seqlen,
+                sequence_start=True,
+                sequence_end=True):
+            timestamps.append(time.perf_counter())
+            tokens.append(token)
+
+        first_token_latency = timestamps[0] - start
+        token_latency = timestamps[-1] - timestamps[0]
+        token = tokens[-1] - tokens[0]
+        stats.append([first_token_latency, token, token_latency])
+        chatbot.reset_session()
+    que.put((session_id, stats))
+
+
+def warmup(tritonserver_addr: str,
+           model_name: str,
+           concurrency: int,
+           session_len: int,
+           output_seqlen: int,
+           warmup_round: int = 4):
+    print('start to warmup ...')
+
+    def _infer(_chatbot, session_id):
+        for _ in range(warmup_round):
+            for _, _, _ in chatbot.stream_infer(
+                    session_id,
+                    prompt='',
+                    request_output_len=output_seqlen,
+                    sequence_start=True,
+                    sequence_end=True):
+                continue
+            chatbot.reset_session()
+
+    _start = time.perf_counter()
+    chatbots = [
+        Chatbot(tritonserver_addr=tritonserver_addr,
+                model_name=model_name,
+                session_len=session_len,
+                ignore_eos=True,
+                profile_generation=True) for _ in range(concurrency)
+    ]
+    procs = []
+    for i, chatbot in enumerate(chatbots):
+        proc = mp.Process(target=_infer, args=(chatbot, i + 1))
+        procs.append(proc)
+        proc.start()
+    for proc in procs:
+        proc.join()
+    _end = time.perf_counter()
+    print(f'end warmup, elapsed time: {round(_end - _start, 2)}s')
+
+
+def main(tritonserver_addr: str,
+         model_name: str,
+         concurrency: int = 1,
+         session_len: int = 2048,
+         input_seqlen: int = 0,
+         output_seqlen: int = 512,
+         test_round: int = 10):
+    warmup(tritonserver_addr, model_name, concurrency, session_len,
+           output_seqlen)
+
+    # make up a prompt that can be tokenized into {input_seqlen} tokens
+    prompt = '' if input_seqlen == 0 else 'hi' + ' hi' * (input_seqlen - 1)
+    que = mp.Queue()
+    procs = []
+    _start = time.perf_counter()
+    for i in range(concurrency):
+        chatbot = Chatbot(tritonserver_addr=tritonserver_addr,
+                          model_name=model_name,
+                          session_len=session_len,
+                          ignore_eos=True,
+                          profile_generation=True)
+        proc = mp.Process(target=infer,
+                          args=(chatbot, i + 1, prompt, output_seqlen,
+                                test_round, que))
+        procs.append(proc)
+        proc.start()
+    for proc in procs:
+        proc.join()
+    _end = time.perf_counter()
+    elapsed_time = _end - _start
+
+    stats = []
+    while not que.empty():
+        session_id, _stats = que.get()
+        print(f'\n{"-" * 50}\n'
+              f'session {session_id} stats: \n{_stats}\n{"-" * 50}\n')
+        stats.append(_stats)
+
+    stats = np.array(stats).reshape(-1, 3)
+
+    first_token_latency_min = np.min(stats[:, 0], axis=0)
+    first_token_latency_max = np.max(stats[:, 0], axis=0)
+    first_token_latency_ave = np.mean(stats[:, 0], axis=0)
+    token_latency_min = np.min(stats[:, 2], axis=0)
+    token_latency_max = np.max(stats[:, 2], axis=0)
+    token_latency_ave = np.mean(stats[:, 2], axis=0)
+    throughput = np.sum(stats[:, 1], axis=0) / np.sum(stats[:, 2], axis=0)
+    print(f'\n{"-" * 50}\ncocurrency: {concurrency}, input_tokens: '
+          f'{input_seqlen}, output_tokens: {output_seqlen}\n'
+          f'elapsed_time: {elapsed_time:.2f}s\n'
+          f'first_token latency(min, max, ave): '
+          f'{first_token_latency_min:.2f}s, {first_token_latency_max:.2f}s, '
+          f'{first_token_latency_ave:.2f}s\ntoken latency(min, max, ave): '
+          f'{token_latency_min:.2f}s, {token_latency_max:.2f}s, '
+          f'{token_latency_ave:.2f}s\n'
+          f'throughput: {throughput} token/s\n{"-" * 50}')
+
+
+if __name__ == '__main__':
+    fire.Fire(main)

benchmark/profile_serving.py

+import json
+import multiprocessing as mp
+import os
+import random
+import time
+from typing import List
+
+import fire
+import numpy as np
+from sentencepiece import SentencePieceProcessor
+
+from llmdeploy.serve.fastertransformer.chatbot import Chatbot
+
+
+class Tokenizer:
+
+    def __init__(self, model_path: str):
+        # reload tokenizer
+        assert os.path.isfile(model_path), model_path
+        self.sp_model = SentencePieceProcessor(model_file=model_path)
+
+    def encode(self, prompts: List):
+        prompts_token_ids = self.sp_model.Encode(prompts,
+                                                 add_bos=False,
+                                                 add_eos=False)
+        return [len(token_ids) for token_ids in prompts_token_ids]
+
+
+def infer(chatbot, session_id: int, req_que: mp.Queue, res_que: mp.Queue):
+    stats = []
+    while not req_que.empty():
+        prompt, input_seqlen, output_seqlen = req_que.get()
+        print(f'request info: session {session_id}, '
+              f'input_seqlen {input_seqlen}, output_seqlen {output_seqlen}')
+        timestamps = []
+        tokens = []
+        start = time.perf_counter()
+        for status, res, token in chatbot.stream_infer(
+                session_id,
+                prompt,
+                request_output_len=output_seqlen,
+                sequence_start=True,
+                sequence_end=True):
+            timestamps.append(time.perf_counter())
+            tokens.append(token)
+        chatbot.reset_session()
+
+        first_token_latency = timestamps[1] - start
+        token_latency = timestamps[-1] - timestamps[0]
+        token = tokens[-1] - tokens[0]
+        stats.append([first_token_latency, token, token_latency])
+    res_que.put((session_id, stats))
+
+
+def warmup(tritonserver_addr: str,
+           model_name: str,
+           concurrency: int,
+           session_len: int,
+           output_seqlen: int,
+           warmup_round: int = 4):
+    print('start to warmup ...')
+
+    def _infer(_chatbot, session_id):
+        for _ in range(warmup_round):
+            for _, _, _ in chatbot.stream_infer(
+                    session_id,
+                    prompt='',
+                    request_output_len=output_seqlen,
+                    sequence_start=True,
+                    sequence_end=True):
+                continue
+            chatbot.reset_session()
+
+    _start = time.perf_counter()
+    chatbots = [
+        Chatbot(tritonserver_addr=tritonserver_addr,
+                model_name=model_name,
+                session_len=session_len,
+                ignore_eos=True,
+                profile_generation=True) for _ in range(concurrency)
+    ]
+    procs = []
+    for i, chatbot in enumerate(chatbots):
+        proc = mp.Process(target=_infer, args=(chatbot, i + 1))
+        procs.append(proc)
+        proc.start()
+    for proc in procs:
+        proc.join()
+    _end = time.perf_counter()
+    print(f'end warmup, elapsed time: {round(_end - _start, 2)} s')
+
+
+def read_dataset(tritonserver_addr, tokenizer_path: str, dataset_path: str,
+                 samples: int, test_round: int, session_len: int):
+    start = time.perf_counter()
+    with open(dataset_path) as f:
+        dataset = json.load(f)
+        dataset = [data for data in dataset if len(data['conversations']) >= 2]
+        # Only keep the first two turns of each conversation.
+        dataset = [(data['conversations'][0]['value'],
+                    data['conversations'][1]['value']) for data in dataset]
+        prompts = [prompt for prompt, _ in dataset]
+        completions = [completion for _, completion in dataset]
+        print(f'elapsed time for read data: '
+              f'{round(time.perf_counter() - start, 2)} s')
+
+    start = time.perf_counter()
+    tokenizer = Tokenizer(tokenizer_path)
+    prompts_token_lens = tokenizer.encode(prompts)
+    completions_token_lens = tokenizer.encode(completions)
+    print(f'elapsed time for tokenization: '
+          f'{round(time.perf_counter() - start, 2)} s')
+
+    start = time.perf_counter()
+    filtered_dataset = []
+    for (prompt, _), input_len, output_len in zip(dataset, prompts_token_lens,
+                                                  completions_token_lens):
+        if input_len + output_len > session_len:
+            # ignore too long conversation
+            continue
+        filtered_dataset.append([prompt, input_len, output_len])
+
+    if samples > 0:
+        filtered_dataset = random.sample(filtered_dataset, samples)
+
+    filtered_dataset *= test_round
+    random.shuffle(filtered_dataset)
+    que = mp.Queue()
+    for data in filtered_dataset:
+        que.put(data)
+    print(f'elapsed time for filtering: '
+          f'{round(time.perf_counter() - start, 2)} s')
+    return que
+
+
+def main(tritonserver_addr: str,
+         model_name: str,
+         tokenizer_path: str,
+         dataset_path: str,
+         concurrency: int = 1,
+         session_len: int = 2048,
+         samples: int = 2000,
+         test_round: int = 1):
+    warmup(tritonserver_addr, model_name, concurrency, session_len,
+           session_len)
+    req_que = read_dataset(tritonserver_addr, tokenizer_path, dataset_path,
+                           samples, test_round, session_len)
+    res_que = mp.Queue()
+    procs = []
+    _start = time.perf_counter()
+    for i in range(concurrency):
+        chatbot = Chatbot(tritonserver_addr=tritonserver_addr,
+                          model_name=model_name,
+                          session_len=session_len,
+                          display=False,
+                          profile_serving=True,
+                          ignore_eos=True)
+        proc = mp.Process(target=infer,
+                          args=(chatbot, i + 1, req_que, res_que))
+        procs.append(proc)
+        proc.start()
+    for proc in procs:
+        proc.join()
+    _end = time.perf_counter()
+    elapsed_time = _end - _start
+
+    stats = []
+    while not res_que.empty():
+        session_id, _stats = res_que.get()
+        print(f'\n{"-" * 50}\n'
+              f'session {session_id} stats: \n{_stats}\n{"-" * 50}\n')
+        stats.append(_stats)
+
+    stats = np.array(stats).reshape(-1, 3)
+
+    first_token_latency_min = np.min(stats[:, 0], axis=0)
+    first_token_latency_max = np.max(stats[:, 0], axis=0)
+    first_token_latency_ave = np.mean(stats[:, 0], axis=0)
+    throughput = np.sum(stats[:, 1], axis=0) / elapsed_time
+    print(f'\n{"-" * 50}\ncocurrency: {concurrency}\n'
+          f'elapsed_time: {elapsed_time:.2f}s\n'
+          f'first_token latency(min, max, ave): '
+          f'{first_token_latency_min:.2f}s, {first_token_latency_max:.2f}s, '
+          f'{first_token_latency_ave:.2f}s\n'
+          f'throughput: {throughput:.2f} token/s\n{"-" * 50}')
+
+
+if __name__ == '__main__':
+    fire.Fire(main)

llmdeploy/model.py

+# Copyright (c) OpenMMLab. All rights reserved.
+from mmengine import Registry
+
+MODELS = Registry('model', locations=['llmdeploy.model'])
+
+
+@MODELS.register_module(name='vicuna')
+class Vicuna:
+
+    def __init__(self):
+        self.system = """A chat between a curious user and an artificial intelligence assistant. The assistant gives helpful, detailed, and polite answers to the user's questions. """  # noqa: E501
+        self.user = 'USER'
+        self.assistant = 'ASSISTANT'
+
+    def get_prompt(self, prompt, sequence_start=True):
+        if sequence_start:
+            return f'{self.system} {self.user}: {prompt} {self.assistant}:'
+        else:
+            return f'</s>{self.user}: {prompt} {self.assistant}:'
+
+    @property
+    def stop_words(self):
+        return None
+
+
+@MODELS.register_module(name='puyu')
+class Puyu:
+
+    def __init__(self):
+        self.system = """meta instruction
+You are an AI assistant whose name is InternLM (书生·浦语).
+- 书生·浦语 is a conversational language model that is developed by Shanghai AI Laboratory (上海人工智能实验室). It is designed to be helpful, honest, and harmless.
+- 书生·浦语 can understand and communicate fluently in the language chosen by the user such as English and 中文.
+conversation"""  # noqa: E501
+        self.user = '<|Human|>'
+        self.eou = 'െ'
+        self.assistant = '<|Assistant|>'
+
+    def get_prompt(self, prompt, sequence_start=True):
+        if sequence_start:
+            return f'{self.system}\n' \
+                   f'{self.user}:{prompt}{self.eou}\n' \
+                   f'{self.assistant}:'
+        else:
+            return f'\n{self.user}:{prompt}{self.eou}\n{self.assistant}:'
+
+    @property
+    def stop_words(self):
+        return [45623]
+
+
+def main(model_name: str = 'test'):
+    assert model_name in MODELS.module_dict.keys(), \
+        f"'{model_name}' is not supported. " \
+        f'The supported models are: {MODELS.module_dict.keys()}'
+    model = MODELS.get('vicuna--1')()
+    prompt = model.get_prompt(prompt='hi')
+    print(prompt)
+
+
+if __name__ == '__main__':
+    import fire
+    fire.Fire(main)

llmdeploy/serve/client.py

@@ -12,9 +12,9 @@ def input_prompt():
     return '\n'.join(iter(input, sentinel))
 
 
-def main(triton_server_addr: str, model_name: str, session_id: int):
+def main(tritonserver_addr: str, model_name: str, session_id: int = 1):
     log_level = os.environ.get('SERVICE_LOG_LEVEL', 'INFO')
-    chatbot = Chatbot(triton_server_addr,
+    chatbot = Chatbot(tritonserver_addr,
                       model_name,
                       log_level=log_level,
                       display=True)

llmdeploy/serve/fastertransformer/chatbot.py

@@ -15,6 +15,7 @@ import numpy as np
 import tritonclient.grpc as grpcclient
 from tritonclient.grpc.service_pb2 import ModelInferResponse
 
+from llmdeploy.model import MODELS
 from llmdeploy.serve.fastertransformer.utils import (Postprocessor,
                                                      Preprocessor,
                                                      prepare_tensor)
@@ -24,9 +25,9 @@ from llmdeploy.serve.fastertransformer.utils import (Postprocessor,
 class Session:
     session_id: Union[int, str]
     request_id: str = ''
-    prev: str = ''  # history of the session in text format
-    round_prev: str = ''  # previous generated text in the current round
+    histories: str = ''  # history conversations of the session
     sequence_length: int = 0  # the total generated token number in the session
+    prompt: str = ''
     response: str = ''
     status: int = None  # status of the session
 
@@ -71,11 +72,9 @@ class Chatbot:
         temperature (float): to modulate the next token probability
         repetition_penalty (float): The parameter for repetition penalty.
             1.0 means no penalty
-        stop_words (list): List of token ids that stops the generation
-        bad_words (list): List of token ids that are not allowed to be
-            generated.
         log_level (int): the level of the log
         display (bool): display the generated text on consolo or not
+        profile_generation (bool): profile token generation or not
     """
 
     def __init__(self,
@@ -86,18 +85,27 @@ class Chatbot:
                  top_k: int = 40,
                  temperature: float = 1.0,
                  repetition_penalty: float = 1.0,
-                 stop_words: List = None,
-                 bad_words: List = None,
+                 ignore_eos: bool = False,
                  log_level: int = logging.INFO,
-                 display: bool = False):
+                 display: bool = False,
+                 profile_generation: bool = False,
+                 profile_serving: bool = False):
+        assert model_name in MODELS.module_dict.keys(), \
+            f"'{model_name}' is not supported. " \
+            f'The supported models are: {MODELS.module_dict.keys()}'
+        self.model_name = model_name
+        self.model = MODELS.get(self.model_name)()
         self._session = None
         self.tritonserver_addr = tritonserver_addr
-        self.model_name = model_name
-        if stop_words is not None:
-            stop_words = np.array(stop_words, dtype=np.int32)
-        if bad_words is not None:
-            bad_words = np.array(bad_words, dtype=np.int32)
-
+        self.preprocess = Preprocessor(tritonserver_addr)
+        self.postprocess = Postprocessor(tritonserver_addr)
+        self.bos_id = self._get_bos()
+        self.eos_id = self._get_eos()
+        stop_words = self._stop_words(self.model.stop_words)
+        bad_words = None
+        if ignore_eos:
+            stop_words = None
+            bad_words = np.array([[[self.eos_id], [1]]], dtype=np.int32)
         self.cfg = mmengine.Config(
             dict(session_len=session_len,
                  top_p=top_p,
@@ -106,10 +114,10 @@ class Chatbot:
                  repetition_penalty=repetition_penalty,
                  stop_words=stop_words,
                  bad_words=bad_words))
-        self.preprocess = Preprocessor(tritonserver_addr)
-        self.postprocess = Postprocessor(tritonserver_addr)
         self.log_level = log_level
         self.display = display
+        self.profile_generation = profile_generation
+        self.profile_serving = profile_serving
 
     def stream_infer(self,
                      session_id: int,
@@ -152,13 +160,16 @@ class Chatbot:
         self._session.request_id = request_id
         self._session.response = ''
 
-        prompt = self._get_prompt(prompt, sequence_start)
-        for status, res, tokens in self._stream_infer(self._session, prompt,
+        self._session.prompt = self._get_prompt(prompt, sequence_start)
+        for status, res, tokens in self._stream_infer(self._session,
+                                                      self._session.prompt,
                                                       request_output_len,
                                                       sequence_start,
                                                       sequence_end):
             yield status, res, tokens
-        self._session.prev = self._session.prev + self._session.round_prev
+        self._session.histories = \
+            self._session.histories + self._session.prompt + \
+            self._session.response
 
     def end(self, session_id: int, *args, **kwargs):
         """end a session. Triton inference server will release the session's
@@ -237,20 +248,41 @@ class Chatbot:
                 break
         if status == StatusCode.TRITON_STREAM_END:
             logger.info(f'cancel session {session_id} successfully')
-            if prev_session.prev:
+            if prev_session.histories:
                 logger.warn(f'TODO: start to recover session {session_id}')
         else:
             logger.info(f'cancel session {session_id} failed: {res}')
         return status
 
+    def reset_session(self):
+        self._session = None
+
+    def _get_bos(self):
+        token_ids, _ = self.preprocess('<BOS>')
+        return token_ids[0][0]
+
+    def _get_eos(self):
+        token_ids, _ = self.preprocess('<EOS>')
+        return token_ids[0][0]
+
+    def _stop_words(self, stop_words: List[int]):
+        if stop_words is None:
+            return None
+        assert isinstance(stop_words, List) and \
+               all(isinstance(elem, int) for elem in stop_words), \
+               f'stop_words must be a list but got {type(stop_words)}'
+        # each id in stop_words represents a stop word
+        # refer to https://github.com/fauxpilot/fauxpilot/discussions/165 for
+        # detailed explanation about fastertransformer's stop_words
+        stop_word_offsets = range(1, len(stop_words) + 1)
+        stop_words = np.array([[stop_words,
+                                stop_word_offsets]]).astype(np.int32)
+        return stop_words
+
     def _get_prompt(self, prompt: str, sequence_start: bool):
-        if self.model_name == 'vicuna':
-            if sequence_start:
-                return f'USER: {prompt} ASSISTANT:'
-            else:
-                return f'</s>USER: {prompt} ASSISTANT:'
-        else:
+        if self.profile_generation or self.profile_serving:
             return prompt
+        return self.model.get_prompt(prompt, sequence_start)
 
     def _stream_infer(self,
                       session: Session,
@@ -271,9 +303,17 @@ class Chatbot:
                f'request_output_len is supposed to be None or int, ' \
                f'but got {type(request_output_len)}'
 
+        if sequence_start:
+            logger.info(f'session {session.session_id}, clear history since '
+                        f'sequence_start is True')
+            session.histories = ''
+            session.sequence_length = 0
+
         input_ids, input_lengths = self.preprocess(prompt)
         input_tokens = input_lengths.squeeze()
-
+        if self.profile_generation:
+            yield StatusCode.TRITON_STREAM_ING, \
+                  'ignore preprocessing during profiling generation', 0
         if request_output_len is None:
             request_output_len = max(
                 128,
@@ -293,7 +333,7 @@ class Chatbot:
                     f'history tokens: {session.sequence_length}')
 
         preseq_length = session.sequence_length
-        session.round_prev = ''
+        session.response = ''
 
         que = queue.Queue()
         producer = threading.Thread(target=self._stream_producer,
@@ -302,10 +342,9 @@ class Chatbot:
                                           request_output_len, sequence_start,
                                           sequence_end, preseq_length, cancel))
         producer.start()
-        for state, res, tokens in self.stream_consumer(self.postprocess, que,
-                                                       session, preseq_length,
-                                                       cancel, logger,
-                                                       self.display):
+        for state, res, tokens in self.stream_consumer(
+                self.postprocess, que, session, preseq_length, cancel, logger,
+                self.display, self.profile_generation, self.eos_id):
             if state.value < 0:
                 yield state, res, 0
             else:
@@ -382,21 +421,13 @@ class Chatbot:
 
     @staticmethod
     def stream_consumer(postprocess, res_queue, session, preseq_length, cancel,
-                        logger, display):
-
-        def process_response(res):
-            if session.ai_says is None:
-                return res, True
-            index = res.find(session.ai_says)
-            if index == -1:
-                return res, False
-            res = res[index + len(session.ai_says):].replace(session.eoa, '')
-            return res, True
+                        logger, display, profile_generation, eos_id):
 
         while True:
             result = res_queue.get()
             if result is None:
-                yield StatusCode.TRITON_STREAM_END, session.response, \
+                yield StatusCode.TRITON_STREAM_END, \
+                      session.response[len(session.prompt):], \
                       session.sequence_length - preseq_length
                 break
             if 'errcode' in result:
@@ -417,22 +448,35 @@ class Chatbot:
 
                 session.sequence_length = sequence_length.squeeze()
                 sequence_length = sequence_length - preseq_length
+                last_token_id = output_ids[-1][-1][session.sequence_length - 1]
+                if last_token_id == eos_id:
+                    session.sequence_length = session.sequence_length - 1
+                    sequence_length = sequence_length - 1
 
                 output_ids = output_ids.reshape((1, 1, output_ids.shape[-1]))
                 sequence_length = sequence_length.reshape(
                     (1, sequence_length.shape[-1]))
+
+                if profile_generation:
+                    yield (StatusCode.TRITON_STREAM_ING,
+                           'postprocessing is ignored during profiling '
+                           'token generation', sequence_length.squeeze())
+                    continue
                 output_str = postprocess(output_ids[:, :, preseq_length:],
                                          sequence_length)
                 text = output_str[0].decode()
                 if display:
-                    new_text = text[len(session.round_prev):]
+                    new_text = text[len(session.response):]
                     print(new_text, end='', flush=True)
-                session.round_prev = text
-                yield (StatusCode.TRITON_STREAM_ING, session.response,
+                session.response = text
+                if len(session.response) > len(session.prompt):
+                    yield (StatusCode.TRITON_STREAM_ING,
+                           session.response[len(session.prompt):],
                            sequence_length.squeeze())
             except Exception as e:
                 logger.error(f'catch exception: {e}')
 
+        session.response = session.response[len(session.prompt):]
         # put session back to queue so that `_stream_infer` can update it in
         # `self.sessions`
         while not res_queue.empty():

llmdeploy/serve/fastertransformer/triton_models/preprocessing/1/model.py

@@ -21,10 +21,14 @@ class Tokenizer:
 
     def encode(self, s: str):
         add_bos = False
+        add_eos = False
         if s.find('<BOS>') != -1:
             s = s.replace('<BOS>', '')
             add_bos = True
-        return self.model.Encode(s, add_bos=add_bos)
+        if s == '<EOS>':
+            s = ''
+            add_eos = True
+        return self.model.Encode(s, add_bos=add_bos, add_eos=add_eos)
 
     def decode(self, t: List[int]):
         return self.model.Decode(t)