[BugFix] process request.num_cached_tokens if it equals to the initial value (#1468)

Signed-off-by: Junhong Liu <98734602+LJH-LBJ@users.noreply.github.com>
Co-authored-by: Gao Han <gaohan19@huawei.com>

.buildkite/test-ready.yml

@@ -157,7 +157,7 @@ steps:
   #                 type: DirectoryOrCreate
 
   - label: "Omni Model Test"
-    timeout_in_minutes: 15
+    timeout_in_minutes: 17
     depends_on: upload-ready-pipeline
     commands:
       - export VLLM_LOGGING_LEVEL=DEBUG

vllm_omni/core/sched/omni_generation_scheduler.py

@@ -125,6 +125,9 @@ class OmniGenerationScheduler(VLLMScheduler):
                 # Pop the finished request from waiting queue and don't schedule it
                 self.waiting.pop_request()
                 continue
+            # Count the number of prefix cached tokens.
+            if request.num_cached_tokens < 0:
+                request.num_cached_tokens = request.num_computed_tokens
 
             # async_chunk: wait for the first upstream chunk (don't start with placeholders).
             if self.chunk_transfer_adapter is not None and len(request.prompt_token_ids) == 0: