[V1] Adding min tokens/repetition/presence/frequence penalties to V1 sampler (#10681)

Signed-off-by: Sourashis Roy <sroy@roblox.com>
Signed-off-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>
Co-authored-by: Woosuk Kwon <woosuk.kwon@berkeley.edu>

tests/v1/engine/test_engine_core.py

@@ -139,3 +139,41 @@ def test_engine_core(monkeypatch):
         engine_core.abort_requests([req2.request_id, req0.request_id])
         assert len(engine_core.scheduler.waiting) == 0
         assert len(engine_core.scheduler.running) == 0
+
+
+def test_engine_core_advanced_sampling(monkeypatch):
+    """
+    A basic end-to-end test to verify that the engine functions correctly 
+    when additional sampling parameters, such as min_tokens and 
+    presence_penalty, are set.
+    """
+    with monkeypatch.context() as m:
+        m.setenv("VLLM_USE_V1", "1")
+        """Setup the EngineCore."""
+        engine_args = EngineArgs(model=MODEL_NAME)
+        vllm_config = engine_args.create_engine_config(
+            usage_context=UsageContext.UNKNOWN_CONTEXT)
+        executor_class = AsyncLLM._get_executor_cls(vllm_config)
+
+        engine_core = EngineCore(vllm_config=vllm_config,
+                                 executor_class=executor_class,
+                                 usage_context=UsageContext.UNKNOWN_CONTEXT)
+        """Test basic request lifecycle."""
+        # First request.
+        request: EngineCoreRequest = make_request()
+        request.sampling_params = SamplingParams(
+            min_tokens=4,
+            presence_penalty=1.0,
+            frequency_penalty=1.0,
+            repetition_penalty=0.1,
+            stop_token_ids=[1001, 1002],
+        )
+        engine_core.add_request(request)
+        assert len(engine_core.scheduler.waiting) == 1
+        assert len(engine_core.scheduler.running) == 0
+        # Loop through until they are all done.
+        while len(engine_core.step()) > 0:
+            pass
+
+        assert len(engine_core.scheduler.waiting) == 0
+        assert len(engine_core.scheduler.running) == 0

tests/v1/sample/test_sampler.py

@@ -0,0 +1,331 @@
+from typing import List, Set, Tuple
+
+import numpy as np
+import pytest
+import torch
+
+from vllm.utils import make_tensor_with_pad
+from vllm.v1.sample.metadata import SamplingMetadata
+from vllm.v1.sample.sampler import Sampler
+
+VOCAB_SIZE = 1024
+NUM_OUTPUT_TOKENS = 20
+CUDA_DEVICES = [
+    f"cuda:{i}" for i in range(1 if torch.cuda.device_count() == 1 else 2)
+]
+MAX_NUM_PROMPT_TOKENS = 64
+
+
+def _create_fake_logits(batch_size: int, vocab_size: int) -> torch.Tensor:
+    fake_logits = torch.full((batch_size, vocab_size), 1e-2, dtype=torch.float)
+    return fake_logits
+
+
+def _create_penalty_tensor(batch_size: int, penalty_value: float,
+                           device: torch.device) -> torch.Tensor:
+    return torch.full((batch_size, ),
+                      fill_value=penalty_value,
+                      dtype=torch.float,
+                      device=device)
+
+
+def _create_prompt_tokens_tensor(
+    prompt_token_ids: List[List[int]],
+    vocab_size: int,
+    device: torch.device,
+) -> torch.Tensor:
+    return make_tensor_with_pad(
+        prompt_token_ids,
+        pad=vocab_size,
+        device=device,
+        dtype=torch.int64,
+        pin_memory=False,
+    )
+
+
+def _create_default_sampling_metadata(
+    num_output_tokens: int,
+    batch_size: int,
+    vocab_size: int,
+    device: torch.device,
+) -> SamplingMetadata:
+    output_token_ids: List[List[int]] = []
+    prompt_token_ids: List[List[int]] = []
+    for _ in range(batch_size):
+        output_token_ids.append(
+            np.random.randint(0, vocab_size, size=num_output_tokens).tolist())
+        prompt_token_ids.append(
+            np.random.randint(0,
+                              vocab_size,
+                              size=np.random.randint(
+                                  1, MAX_NUM_PROMPT_TOKENS)).tolist())
+    fake_sampling_metadata = SamplingMetadata(
+        temperature=torch.full((batch_size, ), 0.0),
+        all_greedy=True,
+        all_random=False,
+        top_p=torch.empty(batch_size, ),
+        top_k=torch.empty(batch_size, ),
+        no_top_p=True,
+        no_top_k=True,
+        generators={},
+        max_num_logprobs=VOCAB_SIZE,
+        prompt_token_ids=_create_prompt_tokens_tensor(prompt_token_ids,
+                                                      vocab_size, device),
+        output_token_ids=output_token_ids,
+        frequency_penalties=_create_penalty_tensor(batch_size, 0.0, device),
+        presence_penalties=_create_penalty_tensor(batch_size, 0.0, device),
+        repetition_penalties=_create_penalty_tensor(batch_size, 1.0, device),
+        no_penalties=True,
+        min_tokens=[],
+        stop_token_ids=[],
+    )
+    return fake_sampling_metadata
+
+
+def _generate_min_token_penalties_and_stop_tokens(
+    num_output_tokens: int, batch_size: int, vocab_size: int,
+    batch_indices_for_min_token_penalty: List[int]
+) -> Tuple[List[int], List[Set[int]]]:
+    """
+    Generates and returns a list of minimum token penalties (`min_tokens`) 
+    and a corresponding list of stop token IDs (`stop_token_ids`) for each 
+    batch.
+
+    If a batch index is included in `batch_indices_for_min_token_penalty`, 
+    a higher `min_tokens` value is assigned (within a randomized range), 
+    and a random set of stop token IDs is created. Otherwise, a lower 
+    `min_tokens` value is assigned, and the stop token IDs set is empty.   
+    """
+    stop_token_ids: List[Set[int]] = []
+    min_tokens: List[int] = []
+    for index in range(batch_size):
+        if index in batch_indices_for_min_token_penalty:
+            min_tokens.append(
+                np.random.randint(num_output_tokens + 1,
+                                  2 * num_output_tokens))
+            stop_token_ids.append(
+                set(
+                    np.random.randint(0, vocab_size - 1)
+                    for _ in range(np.random.randint(0, vocab_size))))
+
+        else:
+            min_tokens.append(np.random.randint(0, num_output_tokens))
+            stop_token_ids.append(set())
+    return (min_tokens, stop_token_ids)
+
+
+def _create_weighted_output_token_list(
+        batch_size: int,
+        vocab_size: int) -> Tuple[List[List[int]], List[List[int]]]:
+    """
+    Creates an output token list where each token occurs a distinct 
+    number of times.
+
+    For each batch, a random subset of token IDs is selected from the
+    vocabulary. The selected tokens are then added to the output token
+    list, each with a different frequency.
+
+    Returns:
+        Tuple[List[List[int]], List[List[int]]]:
+            - The first element is the output token list, where each sublist 
+              corresponds to a batch and contains tokens with weighted 
+              frequencies.
+            - The second element is a list of distinct token IDs for each
+              batch, ordered by their frequency in the corresponding output
+              list.
+    """
+    output_token_ids: List[List[int]] = []
+    sorted_token_ids_in_output: List[List[int]] = []
+    for _ in range(batch_size):
+        distinct_token_ids = np.random.choice(vocab_size,
+                                              size=np.random.randint(1, 10),
+                                              replace=False).tolist()
+        sorted_token_ids_in_output.append(distinct_token_ids)
+        output_token_ids_for_batch = []
+        for index, token_id in enumerate(distinct_token_ids):
+            output_token_ids_for_batch.extend(
+                [token_id for _ in range(index + 1)])
+        output_token_ids.append(output_token_ids_for_batch)
+    return (output_token_ids, sorted_token_ids_in_output)
+
+
+@pytest.mark.parametrize("device", CUDA_DEVICES)
+@pytest.mark.parametrize("batch_size", [1, 2, 32])
+def test_sampler_min_tokens_penalty(device: str, batch_size: int):
+    """
+    Tests that if the number of output tokens is less than 
+    SamplingParams.min_tokens then we will set the logits for
+    the stop token ids to -inf.
+    """
+    torch.set_default_device(device)
+    fake_logits = _create_fake_logits(batch_size, VOCAB_SIZE)
+    sampling_metadata = _create_default_sampling_metadata(
+        NUM_OUTPUT_TOKENS, batch_size, VOCAB_SIZE, torch.device(device))
+    batch_indices_for_min_token_penalty = np.random.randint(
+        0, batch_size - 1, size=np.random.randint(0, batch_size)).tolist()
+    min_tokens, stop_token_ids = _generate_min_token_penalties_and_stop_tokens(
+        NUM_OUTPUT_TOKENS, batch_size, VOCAB_SIZE,
+        batch_indices_for_min_token_penalty)
+    sampling_metadata.min_tokens = min_tokens
+    sampling_metadata.stop_token_ids = stop_token_ids
+    sampler = Sampler()
+    sampler_output = sampler(fake_logits, sampling_metadata)
+    for batch_idx in range(batch_size):
+        for vocab in range(VOCAB_SIZE):
+            # Verify that the logprobs for stop token ids is set
+            # to -inf.
+            logprob_index = torch.where(
+                sampler_output.logprob_token_ids[batch_idx] ==
+                vocab)[0].item()
+            if vocab in stop_token_ids[batch_idx]:
+                assert sampler_output.logprobs[batch_idx][
+                    logprob_index] == -float("inf")
+            else:
+                assert sampler_output.logprobs[batch_idx][
+                    logprob_index] != -float("inf")
+
+
+@pytest.mark.parametrize("device", CUDA_DEVICES)
+@pytest.mark.parametrize("batch_size", [1, 2, 32])
+@pytest.mark.parametrize("presence_penalty", [-2.0, 2.0])
+def test_sampler_presence_penalty(device: str, batch_size: int,
+                                  presence_penalty: float):
+    """
+    Test to verify that if presence penalty is enabled then tokens
+    are penalized as per their presence in the existing output.
+    """
+    torch.set_default_device(device)
+    # Create fake logits where each token is assigned the same
+    # logit value.
+    fake_logits = _create_fake_logits(batch_size, VOCAB_SIZE)
+    sampling_metadata = _create_default_sampling_metadata(
+        NUM_OUTPUT_TOKENS, batch_size, VOCAB_SIZE, torch.device(device))
+    output_token_ids = sampling_metadata.output_token_ids
+    sampling_metadata.presence_penalties = _create_penalty_tensor(
+        batch_size, presence_penalty, torch.device(device))
+    sampling_metadata.no_penalties = False
+    sampler = Sampler()
+    sampler_output = sampler(fake_logits, sampling_metadata)
+    for batch_idx in range(batch_size):
+        # The logprobs in the SamplerOutput are arranged in descending order.
+        # Since all tokens initially have the same logprobs, the non-penalized
+        # tokens will appear at the beginning, while the penalized tokens
+        #  will appear at the end of the list.
+        penalized_token_id = sampler_output.logprob_token_ids[batch_idx][
+            VOCAB_SIZE - 1]
+        penalized_log_prod = sampler_output.logprobs[batch_idx][VOCAB_SIZE - 1]
+        non_penalized_token_id = sampler_output.logprob_token_ids[batch_idx][0]
+        non_penalized_log_prod = sampler_output.logprobs[batch_idx][0]
+        assert non_penalized_log_prod > penalized_log_prod
+        if presence_penalty > 0:
+            # If `presence_penalty` is set to a value greater than 0, it
+            # indicates a preference for new tokens over those already
+            # present in the output.
+            # Verify that the penalized token ID exists in the output, while the
+            # non-penalized token ID does not.
+            assert penalized_token_id in output_token_ids[batch_idx]
+            assert non_penalized_token_id not in output_token_ids[batch_idx]
+        elif presence_penalty < 0:
+            # If `presence_penalty` is set to a value less than 0, it indicates
+            # a preference for existing tokens over new ones. Verify that the
+            # non-penalized token ID exists in the output, while the penalized
+            # token ID does not.
+            assert non_penalized_token_id in output_token_ids[batch_idx]
+            assert penalized_token_id not in output_token_ids[batch_idx]
+
+
+@pytest.mark.parametrize("device", CUDA_DEVICES)
+@pytest.mark.parametrize("batch_size", [1, 2, 32])
+@pytest.mark.parametrize("frequency_penalty", [-2.0, 2.0])
+def test_sampler_frequency_penalty(device: str, batch_size: int,
+                                   frequency_penalty: float):
+    """
+    Test to verify that if frequency penalty is enabled then tokens are
+    penalized as per their frequency of occurrence.
+    """
+    torch.set_default_device(device)
+    # Create fake logits where each token is assigned the same
+    # logit value.
+    fake_logits = _create_fake_logits(batch_size, VOCAB_SIZE)
+    sampling_metadata = _create_default_sampling_metadata(
+        NUM_OUTPUT_TOKENS, batch_size, VOCAB_SIZE, torch.device(device))
+    sampling_metadata.frequency_penalties = _create_penalty_tensor(
+        batch_size, frequency_penalty, torch.device(device))
+    output_token_ids, sorted_token_ids_in_output = \
+        _create_weighted_output_token_list(batch_size, VOCAB_SIZE)
+    sampling_metadata.output_token_ids = output_token_ids
+    sampling_metadata.no_penalties = False
+    sampler = Sampler()
+    sampler_output = sampler(fake_logits, sampling_metadata)
+    for batch_idx in range(batch_size):
+        logprobs_token_ids = sampler_output.logprob_token_ids[batch_idx]
+        non_penalized_token_id = logprobs_token_ids[0]
+        penalized_token_id = logprobs_token_ids[VOCAB_SIZE - 1]
+        distinct_sorted_token_ids_in_output = \
+            sorted_token_ids_in_output[batch_idx]
+        most_frequent_token_id = distinct_sorted_token_ids_in_output[
+            len(distinct_sorted_token_ids_in_output) - 1]
+        if frequency_penalty > 0:
+            # If `frequency_penalty` is set to > 0, it indicates
+            # a preference for new tokens over existing ones. Verify that the
+            # non-penalized token ID is not present in the output, while the
+            # most penalized token is the one that occurs most frequently in
+            # the output.
+            assert non_penalized_token_id \
+                not in distinct_sorted_token_ids_in_output
+            assert penalized_token_id == most_frequent_token_id
+        elif frequency_penalty < 0:
+            # If `frequency_penalty` is set to < 0, it indicates
+            # a preference for existing tokens over new ones. Verify that the
+            # non-penalized token ID is the one that occurs most frequently
+            # in the output, while the penalized token ID is one that has not
+            # yet appeared.
+            assert non_penalized_token_id == most_frequent_token_id
+            assert penalized_token_id \
+                not in distinct_sorted_token_ids_in_output
+
+
+@pytest.mark.parametrize("device", CUDA_DEVICES)
+@pytest.mark.parametrize("batch_size", [1, 2, 32])
+@pytest.mark.parametrize("repetition_penalty", [0.1, 1.9])
+def test_sampler_repetition_penalty(device: str, batch_size: int,
+                                    repetition_penalty: float):
+    """
+    Test to verify that when the repetition penalty is enabled, tokens 
+    are penalized based on their presence in the prompt or the existing
+    output.
+    """
+    torch.set_default_device(device)
+    # Create fake logits where each token is assigned the same
+    # logit value.
+    fake_logits = _create_fake_logits(batch_size, VOCAB_SIZE)
+    sampling_metadata = _create_default_sampling_metadata(
+        NUM_OUTPUT_TOKENS, batch_size, VOCAB_SIZE, torch.device(device))
+    sampling_metadata.repetition_penalties = _create_penalty_tensor(
+        batch_size, repetition_penalty, torch.device(device))
+    sampling_metadata.no_penalties = False
+    sampler = Sampler()
+    sampler_output = sampler(fake_logits, sampling_metadata)
+    for batch_idx in range(batch_size):
+        logprobs_token_ids = sampler_output.logprob_token_ids[batch_idx]
+        non_penalized_token_id = logprobs_token_ids[0]
+        penalized_token_id = logprobs_token_ids[VOCAB_SIZE - 1]
+        prompt_tokens = sampling_metadata.prompt_token_ids[
+            batch_idx][:].tolist()
+        output_tokens = sampling_metadata.output_token_ids[batch_idx]
+        if repetition_penalty > 1.0:
+            # If `repetition_penalty` > 1.0, verify that the non-penalized
+            # token ID has not been seen before, while the penalized token ID
+            # exists either in the prompt or the output.
+            assert (non_penalized_token_id not in prompt_tokens and \
+                non_penalized_token_id not in output_tokens)
+            assert (penalized_token_id  in prompt_tokens or \
+                penalized_token_id in output_tokens)
+        elif repetition_penalty < 1.0:
+            # If `repetition_penalty` < 1.0, verify that the penalized
+            # token ID has not been seen before, while the non-penalized
+            # token ID exists either in the prompt or the output.
+            assert (penalized_token_id not in prompt_tokens and \
+                penalized_token_id not in output_tokens)
+            assert (non_penalized_token_id  in prompt_tokens or \
+                non_penalized_token_id in output_tokens)

tests/v1/worker/test_gpu_input_batch.py

@@ -0,0 +1,224 @@
+from typing import Dict, List, Set, Tuple
+
+import numpy as np
+import pytest
+import torch
+
+from vllm.sampling_params import SamplingParams
+from vllm.utils import is_pin_memory_available, make_tensor_with_pad
+from vllm.v1.sample.metadata import SamplingMetadata
+from vllm.v1.worker.gpu_input_batch import CachedRequestState, InputBatch
+
+VOCAB_SIZE = 1024
+NUM_OUTPUT_TOKENS = 20
+MAX_PROMPT_SIZE = 100
+CUDA_DEVICES = [
+    f"cuda:{i}" for i in range(1 if torch.cuda.device_count() == 1 else 2)
+]
+MAX_NUM_PROMPT_TOKENS = 64
+
+
+def _remove_requests(
+        input_batch: InputBatch, batch_size: int,
+        reqs: List[CachedRequestState]) -> Tuple[Set[str], List[int]]:
+    """
+    Remove some requests randomly from the batch and returns a Tuple
+    of 1) set of request removed 2) indices of the requests removed
+    ordered in descending order
+    """
+
+    num_reqs_to_remove = np.random.randint(0, batch_size)
+    req_indices_to_remove: Set[int] = set()
+    for _ in range(num_reqs_to_remove):
+        req_index_to_remove = np.random.randint(0, batch_size)
+        req_indices_to_remove.add(req_index_to_remove)
+
+    req_indices_to_remove_list = list(req_indices_to_remove)
+    req_indices_to_remove_list.sort(reverse=True)
+    req_ids_to_remove: Set[str] = set()
+    for index in req_indices_to_remove:
+        input_batch.remove_request(reqs[index].req_id)
+        req_ids_to_remove.add(reqs[index].req_id)
+    return (req_ids_to_remove, req_indices_to_remove_list)
+
+
+def _construct_expected_sampling_metadata(
+        reqs: List[CachedRequestState], req_ids_retained: Set[int],
+        req_id_index_in_input_batch: Dict[str, int],
+        device: torch.device) -> SamplingMetadata:
+    """
+    Constructs and returns the expected SamplingMetadata for this
+    batch.
+    """
+    num_reqs = len(req_ids_retained)
+    output_token_ids: List[List[int]] = [list() for _ in range(num_reqs)]
+    prompt_token_ids: List[List[int]] = [list() for _ in range(num_reqs)]
+    presence_penalties = [0.0 for _ in range(num_reqs)]
+    frequency_penalties = [0.0 for _ in range(num_reqs)]
+    repetition_penalties = [1.0 for _ in range(num_reqs)]
+    top_k = [0 for _ in range(num_reqs)]
+    top_p = [0.0 for _ in range(num_reqs)]
+    temperature = [0.0 for _ in range(num_reqs)]
+    stop_token_ids: List[Set[int]] = [set() for _ in range(num_reqs)]
+    min_tokens = [0 for _ in range(num_reqs)]
+    for req in reqs:
+        if req.req_id not in req_ids_retained:
+            continue
+        index_in_input_batch = req_id_index_in_input_batch[req.req_id]
+        output_token_ids[index_in_input_batch] = req.output_token_ids
+        prompt_token_ids[index_in_input_batch] = req.prompt_token_ids
+        presence_penalties[
+            index_in_input_batch] = req.sampling_params.presence_penalty
+        frequency_penalties[
+            index_in_input_batch] = req.sampling_params.frequency_penalty
+        repetition_penalties[
+            index_in_input_batch] = req.sampling_params.repetition_penalty
+        top_k[index_in_input_batch] = req.sampling_params.top_k
+        top_p[index_in_input_batch] = req.sampling_params.top_p
+        temperature[index_in_input_batch] = req.sampling_params.temperature
+        stop_token_ids[
+            index_in_input_batch] = req.sampling_params.all_stop_token_ids
+        min_tokens[index_in_input_batch] = req.sampling_params.min_tokens
+
+
+    return SamplingMetadata(
+        temperature=torch.tensor(temperature, dtype=torch.float, device=device),
+        all_greedy=False,
+        all_random=True,
+        top_p=torch.tensor(top_p, dtype=torch.float, device=device),
+        top_k=torch.tensor(top_k, dtype=torch.int, device=device),
+        no_top_p=all(x == 1.0 for x in top_p),
+        no_top_k=all(x == 0 for x in top_k),
+        generators={},
+        max_num_logprobs=0,
+        prompt_token_ids= make_tensor_with_pad(
+            prompt_token_ids,
+            pad=VOCAB_SIZE,
+            device=torch.device(device),
+            dtype=torch.int64,
+        ),
+        frequency_penalties=torch.tensor(
+            frequency_penalties, dtype=torch.float,
+            device=device),
+        presence_penalties=torch.tensor(
+            presence_penalties, dtype=torch.float,
+            device=device),
+        repetition_penalties=torch.tensor(
+            repetition_penalties, dtype=torch.float,
+            device=device),
+        output_token_ids=output_token_ids,
+        min_tokens=min_tokens,
+        stop_token_ids=stop_token_ids,
+        no_penalties=(all(x ==0 for x in presence_penalties) and \
+            all(x ==0 for x in frequency_penalties) and \
+                all(x ==1 for x in repetition_penalties))
+    )
+
+
+def _create_sampling_params():
+    return SamplingParams(top_k=np.random.randint(1, 10),
+                          top_p=np.random.uniform(0.0, 1.0),
+                          presence_penalty=np.random.uniform(-2.0, 2.0),
+                          repetition_penalty=np.random.uniform(0.0, 2.0),
+                          frequency_penalty=np.random.uniform(-2.0, 2.0),
+                          min_tokens=np.random.randint(1, 10),
+                          stop_token_ids=[
+                              np.random.randint(0, VOCAB_SIZE)
+                              for _ in range(np.random.randint(10))
+                          ])
+
+
+def _construct_cached_request_state(req_id_suffix: int):
+    prompt_token_ids = [
+        np.random.randint(0, VOCAB_SIZE)
+        for _ in range(np.random.randint(0, MAX_PROMPT_SIZE))
+    ]
+    output_token_ids = [
+        np.random.randint(0, VOCAB_SIZE)
+        for _ in range(np.random.randint(0, NUM_OUTPUT_TOKENS))
+    ]
+    return CachedRequestState(req_id=f"req_id_{req_id_suffix}",
+                              prompt_token_ids=prompt_token_ids,
+                              prompt=None,
+                              sampling_params=_create_sampling_params(),
+                              mm_inputs=[],
+                              mm_positions=[],
+                              block_ids=[],
+                              generator=None,
+                              num_computed_tokens=len(output_token_ids),
+                              output_token_ids=output_token_ids)
+
+
+@pytest.mark.parametrize("device", CUDA_DEVICES)
+@pytest.mark.parametrize("batch_size", [1, 2, 32, 64])
+def test_sampling_metadata_in_input_batch(device: str, batch_size: int):
+    """
+    Tests the logic for managing sampling metadata in the InputBatch.
+
+    This test involves adding a set of requests to the InputBatch,
+    followed by removing a subset of them. Afterward, the batch is compacted,
+    and the `make_sampling_metadata` method is invoked on the batch. The
+    output of `make_sampling_metadata` is then compared against the expected
+    results to ensure correctness.
+    """
+    input_batch: InputBatch = InputBatch(max_num_reqs=batch_size,
+                                         max_model_len=1024,
+                                         max_num_blocks_per_req=10,
+                                         device=torch.device(device),
+                                         pin_memory=is_pin_memory_available(),
+                                         vocab_size=1024)
+    reqs: List[CachedRequestState] = []
+    req_id_reqs = {}
+    req_id_output_token_ids = {}
+    # Add requests
+    for req_index in range(batch_size):
+        req: CachedRequestState = _construct_cached_request_state(req_index)
+        input_batch.add_request(req, req_index)
+        reqs.append(req)
+        req_id_reqs[req.req_id] = req
+        req_id_output_token_ids[req.req_id] = req.output_token_ids
+
+    # Remove some requests
+    req_ids_to_remove, req_indices_to_remove = _remove_requests(
+        input_batch, batch_size, reqs)
+    req_ids_retained = set(req_id_reqs.keys()) - req_ids_to_remove
+
+    # Compact the input batch
+    input_batch.condense(req_indices_to_remove)
+
+    # Generate the sampling metadata
+    sampling_metadata = input_batch.make_sampling_metadata(
+        req_id_output_token_ids, skip_copy=False)
+
+    # Create expected output.
+    expected_sampling_metadata = _construct_expected_sampling_metadata(
+        reqs,
+        req_ids_retained,
+        input_batch.req_id_to_index,
+        device=torch.device(device))
+
+    # Assert the actual and expected output.
+    assert torch.allclose(expected_sampling_metadata.temperature,
+                          sampling_metadata.temperature)
+    assert torch.allclose(expected_sampling_metadata.top_p,
+                          sampling_metadata.top_p)
+    assert torch.allclose(expected_sampling_metadata.top_k,
+                          sampling_metadata.top_k)
+    assert torch.allclose(expected_sampling_metadata.frequency_penalties,
+                          sampling_metadata.frequency_penalties)
+    assert torch.allclose(expected_sampling_metadata.presence_penalties,
+                          sampling_metadata.presence_penalties)
+    assert torch.allclose(expected_sampling_metadata.repetition_penalties,
+                          sampling_metadata.repetition_penalties)
+    assert torch.allclose(expected_sampling_metadata.prompt_token_ids,
+                          sampling_metadata.prompt_token_ids)
+    assert (expected_sampling_metadata.output_token_ids ==
+            sampling_metadata.output_token_ids)
+    assert (
+        expected_sampling_metadata.min_tokens == sampling_metadata.min_tokens)
+    assert (expected_sampling_metadata.stop_token_ids ==
+            sampling_metadata.stop_token_ids)
+    assert (expected_sampling_metadata.no_penalties ==
+            sampling_metadata.no_penalties)
+    assert (expected_sampling_metadata.no_top_p == sampling_metadata.no_top_p)
+    assert (expected_sampling_metadata.no_top_k == sampling_metadata.no_top_k)

vllm/model_executor/layers/sampler.py

@@ -11,6 +11,7 @@ import torch
 import torch.nn as nn
 
 import vllm.envs as envs
+from vllm.model_executor.layers.utils import apply_penalties
 from vllm.model_executor.sampling_metadata import (SamplingMetadata,
                                                    SamplingTensors,
                                                    SequenceGroupToSample)
@@ -258,11 +259,11 @@ class Sampler(nn.Module):
 
         # Apply presence and frequency penalties.
         if do_penalties:
-            logits = _apply_penalties(logits, sampling_tensors.prompt_tokens,
+            logits = apply_penalties(logits, sampling_tensors.prompt_tokens,
-                                      sampling_tensors.output_tokens,
+                                     sampling_tensors.output_tokens,
-                                      sampling_tensors.presence_penalties,
+                                     sampling_tensors.presence_penalties,
-                                      sampling_tensors.frequency_penalties,
+                                     sampling_tensors.frequency_penalties,
-                                      sampling_tensors.repetition_penalties)
+                                     sampling_tensors.repetition_penalties)
 
         # Use float32 to apply temperature scaling.
         # Use in-place division to avoid creating a new tensor.
@@ -336,23 +337,6 @@ class Sampler(nn.Module):
         return self.should_modify_greedy_probs_inplace
 
 
-def _get_bin_counts_and_mask(
-    tokens: torch.Tensor,
-    vocab_size: int,
-    num_seqs: int,
-) -> Tuple[torch.Tensor, torch.Tensor]:
-    # Compute the bin counts for the tokens.
-    # vocab_size + 1 for padding.
-    bin_counts = torch.zeros((num_seqs, vocab_size + 1),
-                             dtype=torch.long,
-                             device=tokens.device)
-    bin_counts.scatter_add_(1, tokens, torch.ones_like(tokens))
-    bin_counts = bin_counts[:, :vocab_size]
-    mask = bin_counts > 0
-
-    return bin_counts, mask
-
-
 def _apply_min_tokens_penalty(
     logits: torch.Tensor,
     sampling_metadata: SamplingMetadata,
@@ -400,29 +384,6 @@ def _apply_min_tokens_penalty(
     return logits
 
 
-def _apply_penalties(logits: torch.Tensor, prompt_tokens_tensor: torch.Tensor,
-                     output_tokens_tensor: torch.Tensor,
-                     presence_penalties: torch.Tensor,
-                     frequency_penalties: torch.Tensor,
-                     repetition_penalties: torch.Tensor) -> torch.Tensor:
-    num_seqs, vocab_size = logits.shape
-    _, prompt_mask = _get_bin_counts_and_mask(prompt_tokens_tensor, vocab_size,
-                                              num_seqs)
-    output_bin_counts, output_mask = _get_bin_counts_and_mask(
-        output_tokens_tensor, vocab_size, num_seqs)
-
-    repetition_penalties = repetition_penalties[:, None].repeat(1, vocab_size)
-    repetition_penalties[~(prompt_mask | output_mask)] = 1.0
-    logits = torch.where(logits > 0, logits / repetition_penalties,
-                         logits * repetition_penalties)
-
-    # We follow the definition in OpenAI API.
-    # Refer to https://platform.openai.com/docs/api-reference/parameter-details
-    logits -= frequency_penalties.unsqueeze_(dim=1) * output_bin_counts
-    logits -= presence_penalties.unsqueeze_(dim=1) * output_mask
-    return logits
-
-
 def _apply_top_k_top_p(
     logits: torch.Tensor,
     p: torch.Tensor,

vllm/model_executor/layers/utils.py

@@ -0,0 +1,57 @@
+"""Utility methods for model layers."""
+from typing import Tuple
+
+import torch
+
+
+def get_token_bin_counts_and_mask(
+    tokens: torch.Tensor,
+    vocab_size: int,
+    num_seqs: int,
+) -> Tuple[torch.Tensor, torch.Tensor]:
+    # Compute the bin counts for the tokens.
+    # vocab_size + 1 for padding.
+    bin_counts = torch.zeros((num_seqs, vocab_size + 1),
+                             dtype=torch.long,
+                             device=tokens.device)
+    bin_counts.scatter_add_(1, tokens, torch.ones_like(tokens))
+    bin_counts = bin_counts[:, :vocab_size]
+    mask = bin_counts > 0
+
+    return bin_counts, mask
+
+
+def apply_penalties(logits: torch.Tensor, prompt_tokens_tensor: torch.Tensor,
+                    output_tokens_tensor: torch.Tensor,
+                    presence_penalties: torch.Tensor,
+                    frequency_penalties: torch.Tensor,
+                    repetition_penalties: torch.Tensor) -> torch.Tensor:
+    """
+    Applies penalties in place to the logits tensor
+    logits : The input logits tensor of shape [num_seqs, vocab_size]
+    prompt_tokens_tensor: A tensor containing the prompt tokens. The prompts 
+        are padded to the maximum prompt length within the batch using 
+        `vocab_size` as the padding value. The value `vocab_size` is used 
+        for padding because it does not correspond to any valid token ID 
+        in the vocabulary.
+    output_tokens_tensor: The output tokens tensor.
+    presence_penalties: The presence penalties of shape (num_seqs, )
+    frequency_penalties: The frequency penalties of shape (num_seqs, )
+    repetition_penalties: The repetition penalties of shape (num_seqs, )
+    """
+    num_seqs, vocab_size = logits.shape
+    _, prompt_mask = get_token_bin_counts_and_mask(prompt_tokens_tensor,
+                                                   vocab_size, num_seqs)
+    output_bin_counts, output_mask = get_token_bin_counts_and_mask(
+        output_tokens_tensor, vocab_size, num_seqs)
+    repetition_penalties = repetition_penalties.unsqueeze_(dim=1).repeat(
+        1, vocab_size)
+    logits[logits > 0] /= torch.where(prompt_mask | output_mask,
+                                      repetition_penalties, 1.0)[logits > 0]
+    logits[logits <= 0] *= torch.where(prompt_mask | output_mask,
+                                       repetition_penalties, 1.0)[logits <= 0]
+    # We follow the definition in OpenAI API.
+    # Refer to https://platform.openai.com/docs/api-reference/parameter-details
+    logits -= frequency_penalties.unsqueeze_(dim=1) * output_bin_counts
+    logits -= presence_penalties.unsqueeze_(dim=1) * output_mask
+    return logits

vllm/v1/sample/metadata.py

@@ -1,5 +1,5 @@
 from dataclasses import dataclass
-from typing import Dict
+from typing import Dict, List, Optional, Set
 
 import torch
 
@@ -19,3 +19,13 @@ class SamplingMetadata:
     generators: Dict[int, torch.Generator]
 
     max_num_logprobs: int
+
+    no_penalties: bool
+    prompt_token_ids: Optional[torch.Tensor]
+    frequency_penalties: torch.Tensor
+    presence_penalties: torch.Tensor
+    repetition_penalties: torch.Tensor
+
+    output_token_ids: List[List[int]]
+    min_tokens: List[int]
+    stop_token_ids: List[Set[int]]

vllm/v1/sample/sampler.py

@@ -1,9 +1,11 @@
 """A layer that samples the next tokens from the model's outputs."""
-from typing import Dict
+from typing import Dict, List, Set, Tuple
 
 import torch
 import torch.nn as nn
 
+from vllm.model_executor.layers.utils import apply_penalties
+from vllm.utils import is_pin_memory_available, make_tensor_with_pad
 from vllm.v1.outputs import SamplerOutput
 from vllm.v1.sample.metadata import SamplingMetadata
 
@@ -17,9 +19,18 @@ class Sampler(nn.Module):
         logits: torch.Tensor,
         sampling_metadata: SamplingMetadata,
     ) -> SamplerOutput:
+        _apply_min_token_penalties(logits, sampling_metadata.output_token_ids,
+                                   sampling_metadata.stop_token_ids,
+                                   sampling_metadata.min_tokens)
+        if not sampling_metadata.no_penalties:
+            assert sampling_metadata.prompt_token_ids is not None
+            _apply_penalties(logits, sampling_metadata.prompt_token_ids,
+                             sampling_metadata.presence_penalties,
+                             sampling_metadata.frequency_penalties,
+                             sampling_metadata.repetition_penalties,
+                             sampling_metadata.output_token_ids)
         logits = self.apply_temperature(logits, sampling_metadata.temperature)
         logits = self.apply_top_k_top_p(logits, sampling_metadata)
-
         probs = self.get_probs(logits)
         sampled = self.sample(probs, sampling_metadata)
         # Use int32 to reduce the tensor size.
@@ -157,3 +168,53 @@ def _apply_top_k_top_p(
     # Re-sort the probabilities.
     logits = logits_sort.scatter(dim=-1, index=logits_idx, src=logits_sort)
     return logits
+
+
+def _apply_min_token_penalties(logits: torch.Tensor,
+                               output_token_ids: List[List[int]],
+                               stop_token_ids: List[Set[int]],
+                               min_tokens: List[int]):
+    """
+    Applies minimum token penalty by setting the logits of the stop tokens
+    to -inf.
+    """
+    min_tokens_logits_to_penalize: List[Tuple[int, int]] = []
+    for index, min_token in enumerate(min_tokens):
+        if (len(output_token_ids[index]) < min_token):
+            for stop_token_id in stop_token_ids[index]:
+                min_tokens_logits_to_penalize.append((index, stop_token_id))
+    if min_tokens_logits_to_penalize:
+        logits[tuple(zip(*min_tokens_logits_to_penalize))] = -float("inf")
+
+
+def _apply_penalties(logits: torch.Tensor, prompt_token_ids: torch.Tensor,
+                     presence_penalties: torch.Tensor,
+                     frequency_penalties: torch.Tensor,
+                     repetition_penalties: torch.Tensor,
+                     output_token_ids: List[List[int]]):
+    """
+    Applies presence, frequency and repetition penalties to the logits.
+    """
+    _, vocab_size = logits.shape
+    output_tokens_t = _convert_to_tensors(output_token_ids, vocab_size,
+                                          logits.device)
+    return apply_penalties(logits, prompt_token_ids, output_tokens_t,
+                           presence_penalties, frequency_penalties,
+                           repetition_penalties)
+
+
+def _convert_to_tensors(output_token_ids: List[List[int]], vocab_size: int,
+                        device: torch.device) -> torch.Tensor:
+    """
+    Convert the different list data structures to tensors.
+    """
+    output_tokens_tensor = make_tensor_with_pad(
+        output_token_ids,
+        # Use the value of vocab_size as a pad since we don't have a
+        # token_id of this value.
+        pad=vocab_size,
+        device="cpu",
+        dtype=torch.int64,
+        pin_memory=is_pin_memory_available(),
+    )
+    return output_tokens_tensor.to(device, non_blocking=True)

vllm/v1/worker/gpu_input_batch.py

@@ -43,12 +43,14 @@ class InputBatch:
         max_num_blocks_per_req: int,
         device: torch.device,
         pin_memory: bool,
+        vocab_size: int,
     ):
         self.max_num_reqs = max_num_reqs
         self.max_model_len = max_model_len
         self.max_num_blocks_per_req = max_num_blocks_per_req
         self.device = device
         self.pin_memory = pin_memory
+        self.vocab_size = vocab_size
 
         self.req_ids: List[Optional[str]] = [None] * max_num_reqs
         self.req_id_to_index: Dict[str, int] = {}
@@ -63,6 +65,7 @@ class InputBatch:
         )
         self.token_ids_cpu = self.token_ids_cpu_tensor.numpy()
         self.num_computed_tokens_cpu = np.empty(max_num_reqs, dtype=np.int32)
+        self.num_prompt_tokens = np.zeros(max_num_reqs, dtype=np.int32)
 
         # Attention-related.
         self.block_table = torch.zeros(
@@ -110,6 +113,50 @@ class InputBatch:
         self.top_k_cpu = self.top_k_cpu_tensor.numpy()
         self.top_k_reqs: Set[str] = set()
 
+        # Frequency penalty related data structures
+        self.frequency_penalties = torch.empty((max_num_reqs, ),
+                                               dtype=torch.float,
+                                               device=device)
+        self.frequency_penalties_cpu_tensor = torch.empty(
+            (max_num_reqs, ),
+            dtype=torch.float,
+            device="cpu",
+            pin_memory=pin_memory)
+        self.frequency_penalties_cpu = \
+            self.frequency_penalties_cpu_tensor.numpy()
+        self.frequency_penalties_reqs: Set[str] = set()
+
+        # Presence penalty related data structures
+        self.presence_penalties = torch.empty((max_num_reqs, ),
+                                              dtype=torch.float,
+                                              device=device)
+        self.presence_penalties_cpu_tensor = torch.empty((max_num_reqs, ),
+                                                         dtype=torch.float,
+                                                         device="cpu",
+                                                         pin_memory=pin_memory)
+        self.presence_penalties_cpu = \
+            self.presence_penalties_cpu_tensor.numpy()
+        self.presence_penalties_reqs: Set[str] = set()
+
+        # Repetition penalty related data structures
+        self.repetition_penalties = torch.empty((max_num_reqs, ),
+                                                dtype=torch.float,
+                                                device=device)
+        self.repetition_penalties_cpu_tensor = torch.empty(
+            (max_num_reqs, ),
+            dtype=torch.float,
+            device="cpu",
+            pin_memory=pin_memory)
+        self.repetition_penalties_cpu = \
+            self.repetition_penalties_cpu_tensor.numpy()
+        self.repetition_penalties_reqs: Set[str] = set()
+
+        self.min_tokens: List[int] = [0] * max_num_reqs
+        self.stop_token_ids: List[Set[int]] = [
+            set() for _ in range(max_num_reqs)
+        ]
+        self.prompt_token_ids: Optional[torch.Tensor] = None
+
         # req_index -> generator
         # NOTE(woosuk): The indices of the requests that do not have their own
         # generator should not be included in the dictionary.
@@ -133,6 +180,7 @@ class InputBatch:
 
         # Copy the prompt token ids and output token ids.
         num_prompt_tokens = len(request.prompt_token_ids)
+        self.num_prompt_tokens[req_index] = num_prompt_tokens
         self.token_ids_cpu[
             req_index, :num_prompt_tokens] = request.prompt_token_ids
         start_idx = num_prompt_tokens
@@ -157,6 +205,20 @@ class InputBatch:
         self.top_k_cpu[req_index] = sampling_params.top_k
         if sampling_params.top_k > 0:
             self.top_k_reqs.add(req_id)
+        self.frequency_penalties_cpu[req_index] = \
+            sampling_params.frequency_penalty
+        if sampling_params.frequency_penalty != 0.0:
+            self.frequency_penalties_reqs.add(req_id)
+        self.presence_penalties_cpu[req_index] = \
+            sampling_params.presence_penalty
+        if sampling_params.presence_penalty != 0.0:
+            self.presence_penalties_reqs.add(req_id)
+        self.repetition_penalties_cpu[req_index] = \
+            sampling_params.repetition_penalty
+        if sampling_params.repetition_penalty != 1.0:
+            self.repetition_penalties_reqs.add(req_id)
+        self.min_tokens[req_index] = sampling_params.min_tokens
+        self.stop_token_ids[req_index] = sampling_params.all_stop_token_ids
 
         # NOTE(woosuk): self.generators should not include the requests that
         # do not have their own generator.
@@ -179,6 +241,9 @@ class InputBatch:
         self.random_reqs.discard(req_id)
         self.top_p_reqs.discard(req_id)
         self.top_k_reqs.discard(req_id)
+        self.frequency_penalties_reqs.discard(req_id)
+        self.presence_penalties_reqs.discard(req_id)
+        self.repetition_penalties_reqs.discard(req_id)
         self.generators.pop(req_index, None)
         self.num_logprobs.pop(req_id, None)
         self.prompt_logprob_reqs.discard(req_id)
@@ -191,6 +256,9 @@ class InputBatch:
         self.random_reqs.clear()
         self.top_p_reqs.clear()
         self.top_k_reqs.clear()
+        self.frequency_penalties_reqs.clear()
+        self.presence_penalties_reqs.clear()
+        self.repetition_penalties_reqs.clear()
         self.generators.clear()
         self.num_logprobs.clear()
         self.prompt_logprob_reqs.clear()
@@ -224,6 +292,8 @@ class InputBatch:
             # block_table_cpu.
             self.token_ids_cpu[empty_index] = self.token_ids_cpu[
                 last_req_index]
+            self.num_prompt_tokens[empty_index] = \
+                self.num_prompt_tokens[last_req_index]
             self.num_computed_tokens_cpu[
                 empty_index] = self.num_computed_tokens_cpu[last_req_index]
             self.block_table_cpu[empty_index] = self.block_table_cpu[
@@ -232,6 +302,15 @@ class InputBatch:
                 last_req_index]
             self.top_p_cpu[empty_index] = self.top_p_cpu[last_req_index]
             self.top_k_cpu[empty_index] = self.top_k_cpu[last_req_index]
+            self.frequency_penalties_cpu[empty_index] = \
+                self.frequency_penalties_cpu[last_req_index]
+            self.presence_penalties_cpu[empty_index] = \
+                self.presence_penalties_cpu[last_req_index]
+            self.repetition_penalties_cpu[empty_index] = \
+                self.repetition_penalties_cpu[last_req_index]
+            self.min_tokens[empty_index] = self.min_tokens[last_req_index]
+            self.stop_token_ids[empty_index] = \
+                self.stop_token_ids[last_req_index]
             generator = self.generators.pop(last_req_index, None)
             if generator is not None:
                 self.generators[empty_index] = generator
@@ -241,6 +320,7 @@ class InputBatch:
 
     def make_sampling_metadata(
         self,
+        req_id_output_token_ids: Dict[str, List[int]],
         skip_copy: bool = False,
     ) -> SamplingMetadata:
         if not skip_copy:
@@ -250,6 +330,37 @@ class InputBatch:
                 self.top_p_cpu_tensor[:self.num_reqs], non_blocking=True)
             self.top_k[:self.num_reqs].copy_(
                 self.top_k_cpu_tensor[:self.num_reqs], non_blocking=True)
+            if not self.no_penalties:
+                # Since syncing these tensors is expensive only copy them
+                # if necessary i.e. if there are requests which require
+                # penalties to be applied during sampling.
+                self.frequency_penalties[:self.num_reqs].copy_(
+                    self.frequency_penalties_cpu_tensor[:self.num_reqs],
+                    non_blocking=True)
+                self.presence_penalties[:self.num_reqs].copy_(
+                    self.presence_penalties_cpu_tensor[:self.num_reqs],
+                    non_blocking=True)
+                self.repetition_penalties[:self.num_reqs].copy_(
+                    self.repetition_penalties_cpu_tensor[:self.num_reqs],
+                    non_blocking=True)
+                # The prompt tokens are used only for applying penalties during
+                # the sampling process. Hence copy these tensors only when
+                # there are requests which need penalties to be applied.
+                self.prompt_token_ids = self._make_prompt_token_ids_tensor()
+
+        output_token_ids: List[List[int]] = []
+
+        for req_id in self.req_ids[:self.num_reqs]:
+            assert req_id is not None
+            # Currently we create a tensor for output_token_ids from scratch
+            # at each step. However, for the penalties computation what we
+            # need is stats about the token ids present in the output. This
+            # stats can be maintained incrementally instead of computing it
+            # from scratch at each step.
+            # TODO - Replace this with incremental update to output token
+            # statistics.
+            output_token_ids.append(req_id_output_token_ids[req_id])
+
         return SamplingMetadata(
             temperature=self.temperature[:self.num_reqs],
             all_greedy=self.all_greedy,
@@ -260,8 +371,33 @@ class InputBatch:
             no_top_k=self.no_top_k,
             generators=self.generators,
             max_num_logprobs=self.max_num_logprobs,
+            prompt_token_ids=self.prompt_token_ids,
+            frequency_penalties=self.frequency_penalties[:self.num_reqs],
+            presence_penalties=self.presence_penalties[:self.num_reqs],
+            repetition_penalties=self.repetition_penalties[:self.num_reqs],
+            output_token_ids=output_token_ids,
+            min_tokens=self.min_tokens[:self.num_reqs],
+            stop_token_ids=self.stop_token_ids[:self.num_reqs],
+            no_penalties=self.no_penalties,
         )
 
+    def _make_prompt_token_ids_tensor(self) -> torch.Tensor:
+        max_prompt_len = self.num_prompt_tokens[:self.num_reqs].max()
+        prompt_token_ids_cpu_tensor = torch.empty(
+            (self.num_reqs, max_prompt_len),
+            device="cpu",
+            dtype=torch.int64,
+            pin_memory=self.pin_memory)
+        prompt_token_ids = prompt_token_ids_cpu_tensor.numpy()
+        prompt_token_ids[:] = (
+            self.token_ids_cpu[:self.num_reqs, :max_prompt_len])
+        # Use the value of vocab_size as a pad since we don't have a
+        # token_id of this value.
+        for i in range(self.num_reqs):
+            prompt_token_ids[i, self.num_prompt_tokens[i]:] = self.vocab_size
+        return prompt_token_ids_cpu_tensor.to(device=self.device,
+                                              non_blocking=True)
+
     @property
     def num_reqs(self) -> int:
         return len(self.req_id_to_index)
@@ -282,6 +418,12 @@ class InputBatch:
     def no_top_k(self) -> bool:
         return len(self.top_k_reqs) == 0
 
+    @property
+    def no_penalties(self) -> bool:
+        return (len(self.presence_penalties_reqs) == 0
+                and len(self.frequency_penalties_reqs) == 0
+                and len(self.repetition_penalties_reqs) == 0)
+
     @property
     def max_num_logprobs(self) -> int:
         return max(self.num_logprobs.values()) if self.num_logprobs else 0

vllm/v1/worker/gpu_model_runner.py

@@ -105,6 +105,7 @@ class GPUModelRunner:
             max_num_blocks_per_req=self.max_num_blocks_per_req,
             device=self.device,
             pin_memory=self.pin_memory,
+            vocab_size=model_config.get_vocab_size(),
         )
 
         self.use_cuda_graph = (self.vllm_config.compilation_config.level
@@ -383,7 +384,12 @@ class GPUModelRunner:
                 or scheduler_output.scheduled_resumed_reqs):
             skip_copy = False
         # Create the sampling metadata.
-        sampling_metadata = self.input_batch.make_sampling_metadata(skip_copy)
+        req_id_output_token_ids: Dict[str, List[int]] = \
+            {req_id: req.output_token_ids \
+                for req_id, req in self.requests.items()}
+
+        sampling_metadata = self.input_batch.make_sampling_metadata(
+            req_id_output_token_ids, skip_copy)
         return sampling_metadata
 
     def _execute_encoder(self, scheduler_output: "SchedulerOutput"):