Sync from v0.13

vllm/v1/engine/logprobs.py

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+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+import itertools
+from dataclasses import dataclass
+
+from vllm.logger import init_logger
+from vllm.logprobs import (
+    PromptLogprobs,
+    SampleLogprobs,
+    append_logprobs_for_next_position,
+    create_prompt_logprobs,
+    create_sample_logprobs,
+)
+from vllm.tokenizers.detokenizer_utils import (
+    TokenizerLike,
+    convert_ids_list_to_tokens,
+)
+from vllm.v1.engine import EngineCoreOutput, EngineCoreRequest
+from vllm.v1.outputs import LogprobsLists, LogprobsTensors
+
+logger = init_logger(__name__)
+
+NONES = itertools.repeat(None)
+
+
+@dataclass
+class LogprobsProcessor:
+    # Tokenizer for this request,
+    # None if detokenization is disabled.
+    tokenizer: TokenizerLike | None
+
+    # Logprobs for this request
+    logprobs: SampleLogprobs | None
+    prompt_logprobs: PromptLogprobs | None
+    cumulative_logprob: float | None
+    num_logprobs: int | None
+    num_prompt_logprobs: int | None
+
+    @classmethod
+    def from_new_request(
+        cls,
+        tokenizer: TokenizerLike | None,
+        request: EngineCoreRequest,
+    ) -> "LogprobsProcessor":
+        sampling_params = request.sampling_params
+        assert sampling_params is not None
+        num_logprobs = sampling_params.logprobs
+        num_prompt_logprobs = sampling_params.prompt_logprobs
+        return cls(
+            tokenizer=tokenizer,
+            cumulative_logprob=(None if num_logprobs is None else 0.0),
+            logprobs=(
+                None
+                if num_logprobs is None
+                else create_sample_logprobs(sampling_params.flat_logprobs)
+            ),
+            prompt_logprobs=(
+                None
+                if num_prompt_logprobs is None
+                else create_prompt_logprobs(sampling_params.flat_logprobs)
+            ),
+            num_prompt_logprobs=num_prompt_logprobs,
+            num_logprobs=num_logprobs,
+        )
+
+    def _update_sample_logprobs(self, logprobs_lists: LogprobsLists) -> None:
+        """Update with sample logprobs from EngineCore.
+
+        Outer lists are only of len > 1 if EngineCore made
+        >1 tokens in prior step (e.g. in spec decoding).
+
+        Args:
+          logprobs_lists: the lists of logprob tokens, logprobs, and ranks.
+
+        """
+
+        assert self.num_logprobs is not None
+        assert self.logprobs is not None
+        assert self.cumulative_logprob is not None
+
+        token_ids_lst, logprobs_lst, ranks_lst, _ = logprobs_lists
+
+        for rank_np, logprobs_np, token_ids_np in zip(
+            ranks_lst, logprobs_lst, token_ids_lst
+        ):
+            rank = rank_np.tolist()
+            logprobs = logprobs_np.tolist()
+            token_ids = token_ids_np.tolist()
+            # Detokenize (non-incrementally).
+            decoded_tokens = (
+                NONES
+                if self.tokenizer is None
+                else (convert_ids_list_to_tokens(self.tokenizer, token_ids))
+            )
+
+            # Sampler puts the sampled logprob in first.
+            sampled_token_logprob = logprobs[0]
+            self.cumulative_logprob += sampled_token_logprob
+
+            # Update with the Logprob container for this pos.
+            append_logprobs_for_next_position(
+                self.logprobs,
+                token_ids,
+                logprobs,
+                decoded_tokens,
+                rank,
+                self.num_logprobs,
+            )
+
+    def _update_prompt_logprobs(
+        self,
+        prompt_logprobs_tensors: LogprobsTensors,
+    ) -> None:
+        """Update with prompt logprobs from EngineCore.
+
+        Args:
+          prompt_logprobs_tensors: tuple containing the prompt logprobs
+                                   tensors.
+
+        """
+
+        # Prompt logprobs are enabled.
+        assert self.num_prompt_logprobs is not None
+        assert self.prompt_logprobs is not None
+
+        token_ids, logprobs, ranks = prompt_logprobs_tensors
+
+        # Detokenize non-incrementally.
+        # Output is flat: [num_tok, num_lps] -> [num_tok * num_lps]
+        decoded_tokens = (
+            None
+            if self.tokenizer is None
+            else (
+                convert_ids_list_to_tokens(self.tokenizer, token_ids.flatten().tolist())
+            )
+        )
+
+        # Recover shapes.
+        num_prompt_tokens, num_logprobs = logprobs.shape
+
+        # Pythonize the torch tensors.
+        prompt_token_ranks = ranks.tolist()
+        prompt_logprobs = logprobs.tolist()
+        token_ids = token_ids.tolist()
+
+        # Make Logprob for each position.
+        for pos in range(num_prompt_tokens):
+            # Handle flattening.
+            offset = pos * num_logprobs
+            offset_end = offset + num_logprobs
+            decoded_tokens_for_pos = (
+                NONES if decoded_tokens is None else decoded_tokens[offset:offset_end]
+            )
+
+            # Update with the Logprob container for this pos.
+            append_logprobs_for_next_position(
+                self.prompt_logprobs,
+                token_ids[pos],
+                prompt_logprobs[pos],
+                decoded_tokens_for_pos,
+                prompt_token_ranks[pos],
+                self.num_prompt_logprobs,
+            )
+
+    def pop_prompt_logprobs(self) -> PromptLogprobs | None:
+        """Pop and return all request prompt logprobs
+
+        The logprobs processor aggregates prompt chunk logprobs
+        over one or more prefill chunks. This method returns
+        all prompt logprobs at once and then forgets them.
+        Ensures correct RequestOutputKind.DELTA semantics
+        wherein all prompt logprobs are returned at once at
+        the end of prefill.
+
+        Returns:
+          None if prompt logprobs are disabled for this request.
+          List of all prompt logprobs, otherwise.
+        """
+        plp = self.prompt_logprobs
+        if plp:
+            self.prompt_logprobs = []
+        return plp
+
+    def update_from_output(self, output: EngineCoreOutput) -> None:
+        if output.new_logprobs is not None:
+            self._update_sample_logprobs(output.new_logprobs)
+        if output.new_prompt_logprobs_tensors is not None:
+            self._update_prompt_logprobs(output.new_prompt_logprobs_tensors)