support serving in use zero overhead

vllm/engine/async_llm_engine.py

@@ -280,8 +280,6 @@ class _AsyncLLMEngine(LLMEngine):
         """
         # these are cached outputs from previous iterations. None if on first
         # iteration
-        if self.zero_overhead:
-            return self.zero_overhead_step()
         cached_outputs = self.cached_scheduler_outputs[virtual_engine]
         seq_group_metadata_list = cached_outputs.seq_group_metadata_list
         scheduler_outputs = cached_outputs.scheduler_outputs
@@ -728,7 +726,6 @@ class AsyncLLMEngine(EngineClient):
         """Kick the engine to process the waiting requests.
 
         Returns True if there are in-progress requests."""
-
         new_requests, aborted_requests = (
             self._request_tracker.get_new_and_aborted_requests())
 
@@ -748,7 +745,6 @@ class AsyncLLMEngine(EngineClient):
             await self._engine_abort(aborted_requests)
 
         request_outputs = await self.engine.step_async(virtual_engine)
-
         # Put the outputs into the corresponding streams.
         # If used as a callback, then already invoked inside
         # LLMEngine's _process_model_outputs

vllm/engine/llm_engine.py

@@ -10,6 +10,7 @@ from collections import deque
 from contextlib import contextmanager
 from dataclasses import dataclass
 from functools import partial
+import traceback
 from typing import (TYPE_CHECKING, Callable, ClassVar, Deque, Dict, Iterable,
                     List, Mapping, NamedTuple, Optional)
 from typing import Sequence as GenericSequence
@@ -1265,7 +1266,10 @@ class LLMEngine:
                 seq = seq_group.seqs[0]
                 for token_id, seq_id in zip(sample_out_list, sample_out_ids):
                     if seq.seq_id == seq_id:
+                        if type(token_id) is list:
                             sample.output_token = token_id[0]
+                        else:
+                            sample.output_token = token_id
                         seq.fix_last_token_id(sample.output_token)
                         break
 
@@ -1492,8 +1496,12 @@ class LLMEngine:
             >>>     if not (engine.has_unfinished_requests() or example_inputs):
             >>>         break
         """
+        #traceback.print_stack()
         if self.zero_overhead:
-            return self.zero_overhead_step()
+            out = self.zero_overhead_step()
+            if out is None: #the first step need launch twice
+                out = self.zero_overhead_step()
+            return out
 
         if self.parallel_config.pipeline_parallel_size > 1:
             raise NotImplementedError(

vllm/entrypoints/llm.py

@@ -1388,8 +1388,6 @@ class LLM:
         total_out_toks = 0
         while self.llm_engine.has_unfinished_requests():
             step_outputs = self.llm_engine.step()
-            if step_outputs is None:
-                continue
             for output in step_outputs:
                 if output.finished:
                     outputs.append(output)

vllm/model_executor/layers/sampler.py

@@ -477,6 +477,7 @@ def _greedy_sample(
         same as the length of selected_seq_groups. If the corresponding
         seq_group has do_sample=False, tuple contains ([], [])
     """
+    if not d2d_data.zero_overhead:
         samples_lst = samples.tolist()
     sample_idx = 0
     results: SampleResultType = []
@@ -490,6 +491,9 @@ def _greedy_sample(
         assert num_parent_seqs == 1, (
             "Greedy sampling should have only one seq.")
         parent_ids = list(range(num_parent_seqs))
+        if d2d_data.zero_overhead:
+            next_token_ids = [0] #place holder token id
+        else:
             next_token_ids = [samples_lst[sample_idx]]
         results.append((next_token_ids, parent_ids))
         sample_idx += num_parent_seqs
@@ -713,12 +717,12 @@ def get_pythonized_sample_results(
         sample_result_args.beam_search_logprobs,
         sample_result_args.sample_results_dict,
     )
-
     for sampling_type in SamplingType:
         if sampling_type not in sample_metadata:
             continue
         (seq_group_id, seq_groups) = sample_metadata[sampling_type]
         if sampling_type == SamplingType.GREEDY:
+            d2d_data.random_samples = greedy_samples
             sample_results = _greedy_sample(seq_groups, greedy_samples)
         elif sampling_type in (SamplingType.RANDOM, SamplingType.RANDOM_SEED):
             d2d_data.random_samples = multinomial_samples[sampling_type]#记录random_samples的数据