chore(mocker): batch live output signal sends (#7647)

Signed-off-by: PeaBrane <yanrpei@gmail.com>

components/src/dynamo/common/configuration/groups/kv_router_args.py

@@ -35,7 +35,6 @@ _KV_ROUTER_FIELDS: tuple[str, ...] = (
     "router_queue_threshold",
     "router_event_threads",
     "router_enable_cache_control",
-    "min_initial_workers",
     "router_queue_policy",
     "remote_indexer_component",
 )
@@ -61,7 +60,6 @@ class KvRouterConfigBase(ConfigBase):
     router_queue_threshold: Optional[float]
     router_event_threads: int
     router_enable_cache_control: bool
-    min_initial_workers: int
     router_queue_policy: str
     remote_indexer_component: Optional[str]
 
@@ -274,18 +272,6 @@ class KvRouterArgGroup(ArgGroup):
                 "requests with nvext.cache_control."
             ),
         )
-        add_argument(
-            g,
-            flag_name="--router-min-initial-workers",
-            env_var="DYN_ROUTER_MIN_INITIAL_WORKERS",
-            default=1,
-            help=(
-                "KV Router: Minimum number of workers that must be discovered before "
-                "router startup continues. Ignored when skip_initial_worker_wait is enabled."
-            ),
-            arg_type=int,
-            dest="min_initial_workers",
-        )
         add_argument(
             g,
             flag_name="--router-queue-policy",

components/src/dynamo/frontend/frontend_args.py

@@ -50,6 +50,7 @@ class FrontendConfig(KvRouterConfigBase):
     tls_key_path: Optional[pathlib.Path]
 
     router_mode: str
+    min_initial_workers: int
     namespace: Optional[str] = None
     namespace_prefix: Optional[str] = None
     enforce_disagg: bool
@@ -90,6 +91,8 @@ class FrontendConfig(KvRouterConfigBase):
             raise ValueError(
                 "--migration-limit must be between 0 and 4294967295 (0=disabled)"
             )
+        if self.min_initial_workers < 0:
+            raise ValueError("--router-min-initial-workers must be >= 0")
         if self.router_enable_cache_control and self.router_mode != "kv":
             raise ValueError("--enable-cache-control requires --router-mode=kv")
         if self.tokenizer_backend not in self._VALID_TOKENIZER_BACKENDS:
@@ -188,6 +191,20 @@ class FrontendArgGroup(ArgGroup):
             "synchronous prefill path.",
             choices=["round-robin", "random", "power-of-two", "kv", "direct"],
         )
+        add_argument(
+            g,
+            flag_name="--router-min-initial-workers",
+            env_var="DYN_ROUTER_MIN_INITIAL_WORKERS",
+            default=0,
+            help=(
+                "Minimum number of workers required before router startup continues. "
+                "This is exported as DYN_ROUTER_MIN_INITIAL_WORKERS so the generic "
+                "push-router path and the KV router's config-ready worker gate share "
+                "the same startup threshold. Set to 0 to disable the startup wait."
+            ),
+            arg_type=int,
+            dest="min_initial_workers",
+        )
 
         # KV router options (shared with dynamo.router)
         KvRouterArgGroup().add_arguments(parser)

components/src/dynamo/frontend/main.py

@@ -47,6 +47,8 @@ if TYPE_CHECKING:
 configure_dynamo_logging()
 logger = logging.getLogger(__name__)
 
+MIN_INITIAL_WORKERS_ENV = "DYN_ROUTER_MIN_INITIAL_WORKERS"
+
 
 def setup_engine_factory(
     runtime: DistributedRuntime,
@@ -232,6 +234,7 @@ async def async_main():
         router_mode = RouterMode.RoundRobin
         kv_router_config = None
 
+    os.environ[MIN_INITIAL_WORKERS_ENV] = str(config.min_initial_workers)
     router_config = RouterConfig(
         router_mode,
         kv_router_config,

docs/components/router/router-examples.md

@@ -60,6 +60,9 @@ async def main():
         kv_router_config=kv_router_config
     )
 
+    # Optional startup gate shared with the frontend and standalone indexer:
+    # os.environ["DYN_ROUTER_MIN_INITIAL_WORKERS"] = "2"
+
     # Your input tokens
     token_ids = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
 

docs/components/router/standalone-indexer.md

@@ -16,6 +16,10 @@ This is distinct from the [Standalone Router](../../../components/src/dynamo/rou
 
 The HTTP API follows the [Mooncake KV Indexer RFC](https://github.com/kvcache-ai/Mooncake/issues/1403) conventions.
 
+`DYN_ROUTER_MIN_INITIAL_WORKERS` is also honored here. When set to a positive integer, the
+standalone indexer waits for that many workers to register before opening its startup-ready
+gate, matching the frontend/router startup behavior.
+
 ## Multi-Model and Multi-Tenant Support
 
 The indexer maintains one radix tree per `(model_name, tenant_id)` pair. Workers registered with different model names or tenant IDs are isolated into separate indexers — queries against one model/tenant never return scores from another.
@@ -143,6 +147,12 @@ In runtime mode, workers are discovered automatically via MDC. The `--workers` f
 | `--component-name` | `kv-indexer` | Component name for this indexer in the Dynamo runtime |
 | `--worker-component` | `backend` | Component name that workers register under for event-plane subscription |
 
+### Shared Startup Gate
+
+Set `DYN_ROUTER_MIN_INITIAL_WORKERS=<n>` to require at least `<n>` workers before the
+standalone indexer, frontend push-router path, and KV router config-ready gate all proceed.
+Leave it unset or set it to `0` to disable the startup wait.
+
 ## HTTP API
 
 ### `GET /health` — Liveness check

lib/bench/kv_router/active_sequences_bench.rs

@@ -378,8 +378,7 @@ async fn apply_entry(
                 isl,
                 OverlapScores::default(),
             );
-            let _ = multi
-                .add_request(SequenceRequest {
+            let _ = multi.add_request(SequenceRequest {
                 request_id,
                 token_sequence: Some(block_hashes),
                 isl,
@@ -388,14 +387,13 @@ async fn apply_entry(
                 expected_output_tokens: Some(output_length as u32),
                 worker,
                 lora_name: None,
-                })
-                .await;
+            });
         }
         SequenceTraceEntry::PrefillComplete { request_id } => {
-            let _ = multi.mark_prefill_completed(&request_id).await;
+            let _ = multi.mark_prefill_completed(&request_id);
         }
         SequenceTraceEntry::Free { request_id } => {
-            let _ = multi.free(&request_id).await;
+            let _ = multi.free(&request_id);
         }
     }
 }

lib/bench/kv_router/common/mod.rs

@@ -389,7 +389,7 @@ async fn replay_worker_trace(
         .rescale_ready_span(trace_simulation_duration_ms)?
         .into_trace_driver()?;
     let collector = EventCollector::new();
-    let (output_tx, mut output_rx) = mpsc::unbounded_channel::<OutputSignal>();
+    let (output_tx, mut output_rx) = mpsc::unbounded_channel::<Vec<OutputSignal>>();
     let scheduler = Scheduler::new(
         sched_args,
         0,
@@ -429,32 +429,40 @@ async fn replay_worker_trace(
                 let deadline = start + Duration::from_secs_f64((next_ready_ms.max(0.0)) / 1000.0);
                 tokio::select! {
                     maybe_signal = output_rx.recv() => {
-                        let Some(signal) = maybe_signal else {
+                        let Some(output_batch) = maybe_signal else {
                             anyhow::bail!("scheduler ended before workload replay drained");
                         };
+                        let timestamp_us = start.elapsed().as_micros() as u64;
+                        let completion_ms = start.elapsed().as_secs_f64() * 1000.0;
+                        for signal in output_batch {
                             output_signals.push(TimedOutputSignal {
                                 signal: signal.clone(),
-                            timestamp_us: start.elapsed().as_micros() as u64,
+                                timestamp_us,
                             });
                             if signal.completed {
                                 completed_turns += 1;
-                            driver.on_complete(signal.uuid, start.elapsed().as_secs_f64() * 1000.0)?;
+                                driver.on_complete(signal.uuid, completion_ms)?;
+                            }
                         }
                     }
                     _ = tokio::time::sleep_until(deadline) => {}
                 }
             }
             None => {
-                let Some(signal) = output_rx.recv().await else {
+                let Some(output_batch) = output_rx.recv().await else {
                     anyhow::bail!("scheduler ended before workload replay drained");
                 };
+                let timestamp_us = start.elapsed().as_micros() as u64;
+                let completion_ms = start.elapsed().as_secs_f64() * 1000.0;
+                for signal in output_batch {
                     output_signals.push(TimedOutputSignal {
                         signal: signal.clone(),
-                    timestamp_us: start.elapsed().as_micros() as u64,
+                        timestamp_us,
                     });
                     if signal.completed {
                         completed_turns += 1;
-                    driver.on_complete(signal.uuid, start.elapsed().as_secs_f64() * 1000.0)?;
+                        driver.on_complete(signal.uuid, completion_ms)?;
+                    }
                 }
             }
         }

lib/bindings/python/rust/llm/entrypoint.rs

@@ -58,7 +58,7 @@ impl KvRouterConfig {
 #[pymethods]
 impl KvRouterConfig {
     #[new]
-    #[pyo3(signature = (overlap_score_weight=1.0, router_temperature=0.0, use_kv_events=true, durable_kv_events=false, router_replica_sync=false, router_track_active_blocks=true, router_track_output_blocks=false, router_assume_kv_reuse=true, router_track_prefill_tokens=true, router_snapshot_threshold=1000000, router_reset_states=false, router_ttl_secs=120.0, router_max_tree_size=1048576, router_prune_target_ratio=0.8, router_queue_threshold=Some(4.0), router_event_threads=4, router_enable_cache_control=false, min_initial_workers=1, router_queue_policy="fcfs", remote_indexer_component=None))]
+    #[pyo3(signature = (overlap_score_weight=1.0, router_temperature=0.0, use_kv_events=true, durable_kv_events=false, router_replica_sync=false, router_track_active_blocks=true, router_track_output_blocks=false, router_assume_kv_reuse=true, router_track_prefill_tokens=true, router_snapshot_threshold=1000000, router_reset_states=false, router_ttl_secs=120.0, router_max_tree_size=1048576, router_prune_target_ratio=0.8, router_queue_threshold=Some(4.0), router_event_threads=4, router_enable_cache_control=false, router_queue_policy="fcfs", remote_indexer_component=None))]
     #[allow(clippy::too_many_arguments)]
     fn new(
         overlap_score_weight: f64,
@@ -78,7 +78,6 @@ impl KvRouterConfig {
         router_queue_threshold: Option<f64>,
         router_event_threads: u32,
         router_enable_cache_control: bool,
-        min_initial_workers: usize,
         router_queue_policy: &str,
         remote_indexer_component: Option<String>,
     ) -> Self {
@@ -102,7 +101,6 @@ impl KvRouterConfig {
                 router_event_threads,
                 router_enable_cache_control,
                 skip_initial_worker_wait: false,
-                min_initial_workers,
                 router_queue_policy: router_queue_policy.parse().unwrap_or_else(|_| {
                     panic!("invalid router_queue_policy: {router_queue_policy:?}")
                 }),

lib/bindings/python/src/dynamo/_core.pyi

@@ -1179,7 +1179,6 @@ class KvRouterConfig:
         router_queue_threshold: Optional[float] = 4.0,
         router_event_threads: int = 4,
         router_enable_cache_control: bool = False,
-        min_initial_workers: int = 1,
         router_queue_policy: str = "fcfs",
     ) -> None:
         """
@@ -1213,9 +1212,6 @@ class KvRouterConfig:
                 When > 1, uses a concurrent radix tree with a thread pool.
             router_enable_cache_control: Enable cache control (PIN with TTL) via the worker's
                 cache_control service mesh endpoint (default: False).
-            min_initial_workers: Minimum number of discovered workers required before
-                router startup continues (default: 1). Ignored when
-                skip_initial_worker_wait is enabled.
             router_queue_policy: Scheduling policy for the router queue (default: "fcfs").
                 "fcfs": first-come first-served with priority bumps — optimizes tail TTFT.
                 "lcfs": last-come first-served with priority bumps — intentionally worsens tail behavior for policy comparisons.

lib/bindings/python/tests/test_replay.py

@@ -84,7 +84,6 @@ def _router_config_payload():
         "router_prune_target_ratio": 0.8,
         "router_enable_cache_control": False,
         "skip_initial_worker_wait": False,
-        "min_initial_workers": 1,
         "remote_indexer_component": None,
     }
 

lib/kv-router/src/scheduling/config.rs

 // SPDX-FileCopyrightText: Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
 // SPDX-License-Identifier: Apache-2.0
 
+use std::env::{self, VarError};
 use std::fmt;
 use std::str::FromStr;
 
@@ -13,14 +14,26 @@ use crate::protocols::{
     BlockHashOptions, LocalBlockHash, compute_block_hash_for_seq, compute_seq_hash_for_block,
 };
 
-const fn default_min_initial_workers() -> usize {
-    1
-}
-
 const fn default_track_prefill_tokens() -> bool {
     true
 }
 
+pub const DYN_ROUTER_MIN_INITIAL_WORKERS: &str = "DYN_ROUTER_MIN_INITIAL_WORKERS";
+
+pub fn min_initial_workers_from_env() -> anyhow::Result<usize> {
+    match env::var(DYN_ROUTER_MIN_INITIAL_WORKERS) {
+        Ok(value) => value.parse::<usize>().map_err(|error| {
+            anyhow::anyhow!(
+                "{DYN_ROUTER_MIN_INITIAL_WORKERS} must be a non-negative integer, got {value:?}: {error}"
+            )
+        }),
+        Err(VarError::NotPresent) => Ok(0),
+        Err(VarError::NotUnicode(_)) => {
+            anyhow::bail!("{DYN_ROUTER_MIN_INITIAL_WORKERS} must be valid unicode")
+        }
+    }
+}
+
 #[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
 pub enum RouterQueuePolicy {
@@ -149,17 +162,8 @@ pub struct KvRouterConfig {
     /// When false (default), cache_control is ignored and no cache_control client is created.
     pub router_enable_cache_control: bool,
 
-    /// Skip blocking for workers at init time (default: false).
-    /// When true, the router starts immediately without waiting for discovery-based
-    /// workers and workers are provided externally per-request (e.g., EPP).
     pub skip_initial_worker_wait: bool,
 
-    /// Minimum number of workers that must be discovered before router startup continues.
-    /// Default: 1. Ignored when skip_initial_worker_wait=true.
-    #[serde(default = "default_min_initial_workers")]
-    #[validate(range(min = 1))]
-    pub min_initial_workers: usize,
-
     /// Scheduling policy for the router queue.
     /// "fcfs" (default): first-come first-served with priority bumps — optimizes tail TTFT.
     /// "wspt": weighted shortest processing time (Smith's rule) — optimizes average TTFT.
@@ -194,7 +198,6 @@ impl Default for KvRouterConfig {
             router_event_threads: 4,
             router_enable_cache_control: false,
             skip_initial_worker_wait: false,
-            min_initial_workers: default_min_initial_workers(),
             router_queue_policy: RouterQueuePolicy::default(),
             remote_indexer_component: None,
         }
@@ -309,25 +312,11 @@ mod tests {
         assert_eq!(deserialized, RouterQueuePolicy::Lcfs);
     }
 
-    #[test]
-    fn kv_router_config_defaults_to_one_initial_worker() {
-        assert_eq!(KvRouterConfig::default().min_initial_workers, 1);
-    }
-
     #[test]
     fn kv_router_config_defaults_to_tracking_prefill_tokens() {
         assert!(KvRouterConfig::default().router_track_prefill_tokens);
     }
 
-    #[test]
-    fn kv_router_config_rejects_zero_initial_workers() {
-        let cfg = KvRouterConfig {
-            min_initial_workers: 0,
-            ..KvRouterConfig::default()
-        };
-        assert!(cfg.validate().is_err());
-    }
-
     #[test]
     fn compute_seq_hashes_for_tracking_uses_mm_hashes() {
         let cfg = KvRouterConfig::default();

lib/kv-router/src/scheduling/local.rs

@@ -192,19 +192,17 @@ where
     }
 
     pub async fn add_request(&self, req: SequenceRequest) -> Result<(), SequenceError> {
-        self.slots.add_request(req).await
+        self.slots.add_request(req)
     }
 
     pub async fn mark_prefill_completed(&self, request_id: &str) -> Result<(), SequenceError> {
-        self.slots
-            .mark_prefill_completed(&request_id.to_string())
-            .await?;
+        self.slots.mark_prefill_completed(&request_id.to_string())?;
         self.queue.update().await;
         Ok(())
     }
 
     pub async fn free(&self, request_id: &str) -> Result<(), SequenceError> {
-        self.slots.free(&request_id.to_string()).await?;
+        self.slots.free(&request_id.to_string())?;
         self.queue.update().await;
         Ok(())
     }

lib/kv-router/src/scheduling/queue.rs

@@ -231,9 +231,7 @@ impl<
             return;
         };
 
-        if let Err(e) = self
-            .slots
-            .add_request(SequenceRequest {
+        if let Err(e) = self.slots.add_request(SequenceRequest {
             request_id: request_id.clone(),
             token_sequence: request.token_seq,
             isl: request.isl_tokens,
@@ -242,9 +240,7 @@ impl<
             expected_output_tokens: request.expected_output_tokens,
             worker: selection.worker,
             lora_name: request.lora_name.clone(),
-            })
-            .await
-        {
+        }) {
             tracing::warn!("Failed to add request {request_id}: {e}");
         }
     }
@@ -413,8 +409,8 @@ mod tests {
                 let resp = resp.expect("scheduling failed");
                 assert!(resp.best_worker.worker_id < num_workers as u64);
 
-                slots.mark_prefill_completed(&req_id).await.unwrap();
-                slots.free(&req_id).await.unwrap();
+                slots.mark_prefill_completed(&req_id).unwrap();
+                slots.free(&req_id).unwrap();
                 queue.update().await;
             }));
         }
@@ -457,8 +453,8 @@ mod tests {
         for _ in 0..num_requests {
             queue.update().await;
             for rid in &req_ids {
-                let _ = slots.mark_prefill_completed(rid).await;
-                let _ = slots.free(rid).await;
+                let _ = slots.mark_prefill_completed(rid);
+                let _ = slots.free(rid);
             }
         }
         queue.update().await;
@@ -499,11 +495,8 @@ mod tests {
         assert_eq!(queue.pending_count(), 2);
 
         // Free the first request and update — should drain one from pending
-        slots
-            .mark_prefill_completed(&"req-1".to_string())
-            .await
-            .unwrap();
-        slots.free(&"req-1".to_string()).await.unwrap();
+        slots.mark_prefill_completed(&"req-1".to_string()).unwrap();
+        slots.free(&"req-1".to_string()).unwrap();
         queue.update().await;
 
         // After update, one pending request should have been scheduled
@@ -514,11 +507,11 @@ mod tests {
         );
 
         // Free req-2 and update to drain remaining
-        let _ = slots.mark_prefill_completed(&"req-2".to_string()).await;
-        let _ = slots.free(&"req-2".to_string()).await;
+        let _ = slots.mark_prefill_completed(&"req-2".to_string());
+        let _ = slots.free(&"req-2".to_string());
         queue.update().await;
-        let _ = slots.mark_prefill_completed(&"req-3".to_string()).await;
-        let _ = slots.free(&"req-3".to_string()).await;
+        let _ = slots.mark_prefill_completed(&"req-3".to_string());
+        let _ = slots.free(&"req-3".to_string());
         queue.update().await;
 
         assert_eq!(queue.pending_count(), 0, "all requests should be drained");
@@ -598,9 +591,8 @@ mod tests {
         // Clean up
         slots
             .mark_prefill_completed(&"after-register".to_string())
-            .await
             .unwrap();
-        slots.free(&"after-register".to_string()).await.unwrap();
+        slots.free(&"after-register".to_string()).unwrap();
     }
 
     /// Register_workers is additive: calling with a new set does NOT remove old workers.
@@ -651,8 +643,8 @@ mod tests {
                 .expect("oneshot dropped")
                 .expect("scheduling failed");
             seen.insert(resp.best_worker.worker_id);
-            slots.mark_prefill_completed(&req_id).await.unwrap();
-            slots.free(&req_id).await.unwrap();
+            slots.mark_prefill_completed(&req_id).unwrap();
+            slots.free(&req_id).unwrap();
         }
 
         assert!(
@@ -721,9 +713,8 @@ mod tests {
         );
         slots
             .mark_prefill_completed(&"filter-0".to_string())
-            .await
             .unwrap();
-        slots.free(&"filter-0".to_string()).await.unwrap();
+        slots.free(&"filter-0".to_string()).unwrap();
     }
 
     #[tokio::test(flavor = "multi_thread")]
@@ -747,9 +738,9 @@ mod tests {
         let _resp2 = rx2.await.unwrap().unwrap();
         assert_eq!(queue.pending_count(), 0);
 
-        let _ = slots.mark_prefill_completed(&"req-1".to_string()).await;
-        let _ = slots.free(&"req-1".to_string()).await;
-        let _ = slots.mark_prefill_completed(&"req-2".to_string()).await;
-        let _ = slots.free(&"req-2".to_string()).await;
+        let _ = slots.mark_prefill_completed(&"req-1".to_string());
+        let _ = slots.free(&"req-1".to_string());
+        let _ = slots.mark_prefill_completed(&"req-2".to_string());
+        let _ = slots.free(&"req-2".to_string());
     }
 }

lib/kv-router/src/sequences/multi_worker.rs

@@ -83,12 +83,6 @@ pub enum SequenceError {
 
     #[error("Request {request_id} not found")]
     RequestNotFound { request_id: String },
-
-    #[error("Failed to publish event: {0}")]
-    PublishFailed(#[from] anyhow::Error),
-
-    #[error("Synchronous mutation requires replica_sync=false")]
-    SyncMutationRequiresNoReplicaSync,
 }
 
 /// Bundled parameters for adding a request to the sequence tracker.
@@ -147,7 +141,7 @@ pub struct ActiveSequencesMultiWorker<P: SequencePublisher> {
     request_to_lora: DashMap<RequestId, String>,
     block_size: usize,
     router_id: u64,
-    publisher: P,
+    publisher: Arc<P>,
     replica_sync: bool,
     worker_type: &'static str,
 }
@@ -172,12 +166,29 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
             request_to_lora: DashMap::new(),
             block_size,
             router_id,
-            publisher,
+            publisher: Arc::new(publisher),
             replica_sync,
             worker_type,
         }
     }
 
+    fn spawn_publish_event(&self, event: ActiveSequenceEvent) {
+        if !self.replica_sync {
+            return;
+        }
+
+        let publisher = Arc::clone(&self.publisher);
+        tokio::spawn(async move {
+            if let Err(e) = publisher.publish_event(&event).await {
+                tracing::error!(
+                    request_id = %event.request_id,
+                    worker = ?event.worker,
+                    "failed to publish active sequence event: {e}"
+                );
+            }
+        });
+    }
+
     /// Spawn a background task that subscribes to replica-sync events from peer routers
     /// and applies them to the local state.
     pub fn start_replica_sync<S: SequenceSubscriber + 'static>(
@@ -370,13 +381,6 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
         }
     }
 
-    fn ensure_sync_mutation_allowed(&self) -> Result<(), SequenceError> {
-        if self.replica_sync {
-            return Err(SequenceError::SyncMutationRequiresNoReplicaSync);
-        }
-        Ok(())
-    }
-
     fn add_request_local(&self, req: SequenceRequest) -> Result<(), SequenceError> {
         let SequenceRequest {
             request_id,
@@ -433,9 +437,8 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
         Ok(())
     }
 
-    pub async fn add_request(&self, req: SequenceRequest) -> Result<(), SequenceError> {
-        if self.replica_sync {
-            let event = ActiveSequenceEvent {
+    pub fn add_request(&self, req: SequenceRequest) -> Result<(), SequenceError> {
+        self.spawn_publish_event(ActiveSequenceEvent {
             request_id: req.request_id.clone(),
             worker: req.worker,
             data: ActiveSequenceEventData::AddRequest {
@@ -447,15 +450,7 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
             },
             router_id: self.router_id,
             lora_name: req.lora_name.clone(),
-            };
-            self.publisher.publish_event(&event).await?;
-        }
-
-        self.add_request_local(req)
-    }
-
-    pub fn add_request_sync(&self, req: SequenceRequest) -> Result<(), SequenceError> {
-        self.ensure_sync_mutation_allowed()?;
+        });
         self.add_request_local(req)
     }
 
@@ -495,7 +490,7 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
         Ok(())
     }
 
-    async fn mutate_request_worker(
+    fn mutate_request_worker(
         &self,
         request_id: &RequestId,
         event_data: ActiveSequenceEventData,
@@ -510,21 +505,17 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
                 request_id: request_id.clone(),
             })?;
 
-        if self.replica_sync {
         let lora_name = self
             .request_to_lora
             .get(request_id)
             .map(|entry| entry.value().clone());
-
-            let event = ActiveSequenceEvent {
+        self.spawn_publish_event(ActiveSequenceEvent {
             request_id: request_id.clone(),
             worker,
             data: event_data,
             router_id: self.router_id,
             lora_name,
-            };
-            self.publisher.publish_event(&event).await?;
-        }
+        });
 
         self.mutate_request_worker_local(request_id, mutate_fn, remove_mapping)
     }
@@ -537,7 +528,7 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
     /// This also performs the underlying prefill-complete cleanup via
     /// [`ActiveSequences::free`], so callers do not need to call
     /// [`Self::mark_prefill_completed`] before freeing a completed request.
-    pub async fn free(&self, request_id: &RequestId) -> Result<(), SequenceError> {
+    pub fn free(&self, request_id: &RequestId) -> Result<(), SequenceError> {
         if !self.request_to_worker.contains_key(request_id) {
             tracing::debug!("Request {request_id} not found, already freed (idempotent)");
             return Ok(());
@@ -551,32 +542,13 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
             },
             true,
         )
-        .await
-    }
-
-    pub fn free_sync(&self, request_id: &RequestId) -> Result<(), SequenceError> {
-        self.ensure_sync_mutation_allowed()?;
-        if !self.request_to_worker.contains_key(request_id) {
-            tracing::debug!("Request {request_id} not found, already freed (idempotent)");
-            return Ok(());
-        }
-        self.mutate_request_worker_local(
-            request_id,
-            |seqs, rid| {
-                seqs.free(rid);
-            },
-            true,
-        )
     }
 
     /// Mark prefill as completed for a request.
     ///
     /// Note: Calling this multiple times for the same request is allowed and will be a no-op
     /// after the first call (idempotent).
-    pub async fn mark_prefill_completed(
-        &self,
-        request_id: &RequestId,
-    ) -> Result<(), SequenceError> {
+    pub fn mark_prefill_completed(&self, request_id: &RequestId) -> Result<(), SequenceError> {
         self.mutate_request_worker(
             request_id,
             ActiveSequenceEventData::MarkPrefillCompleted,
@@ -585,18 +557,6 @@ impl<P: SequencePublisher + 'static> ActiveSequencesMultiWorker<P> {
             },
             false,
         )
-        .await
-    }
-
-    pub fn mark_prefill_completed_sync(&self, request_id: &RequestId) -> Result<(), SequenceError> {
-        self.ensure_sync_mutation_allowed()?;
-        self.mutate_request_worker_local(
-            request_id,
-            |seqs, rid| {
-                seqs.mark_prefill_completed(rid);
-            },
-            false,
-        )
     }
 
     /// Add an output block with optional fractional decay weight.
@@ -895,7 +855,6 @@ mod tests {
                 worker,
                 lora_name: None,
             })
-            .await
             .unwrap();
 
         assert_eq!(sequences.active_tokens().get(&worker).copied(), Some(0));

lib/kv-router/src/standalone_indexer/mod.rs

@@ -11,10 +11,12 @@ pub mod runtime;
 pub mod server;
 
 use std::sync::Arc;
+use std::time::Duration;
 
 use tokio::net::TcpListener;
 use tokio_util::sync::CancellationToken;
 
+use crate::config::min_initial_workers_from_env;
 use registry::WorkerRegistry;
 use server::{AppState, create_router};
 
@@ -198,6 +200,33 @@ pub async fn run_with_runtime(
     run_common(&config, &registry, cancel_token).await
 }
 
+async fn wait_for_min_initial_workers(
+    registry: &WorkerRegistry,
+    cancel_token: &CancellationToken,
+) -> anyhow::Result<()> {
+    let min_initial_workers = min_initial_workers_from_env()?;
+    if min_initial_workers == 0 {
+        return Ok(());
+    }
+
+    loop {
+        let registered_workers = registry.list().len();
+        if registered_workers >= min_initial_workers {
+            return Ok(());
+        }
+
+        tokio::select! {
+            _ = cancel_token.cancelled() => {
+                anyhow::bail!(
+                    "shutdown triggered before {} indexer workers appeared",
+                    min_initial_workers
+                );
+            }
+            _ = tokio::time::sleep(Duration::from_millis(100)) => {}
+        }
+    }
+}
+
 async fn run_common(
     config: &IndexerConfig,
     registry: &Arc<WorkerRegistry>,
@@ -245,6 +274,7 @@ async fn run_common(
         }
     }
 
+    wait_for_min_initial_workers(registry, &cancel_token).await?;
     registry.signal_ready();
 
     #[cfg(feature = "metrics")]

lib/llm/src/discovery/model_manager.rs

@@ -555,6 +555,7 @@ impl ModelManager {
 
     // -- KV Router creation --
 
+    #[allow(clippy::too_many_arguments)]
     pub async fn kv_chooser_for(
         &self,
         endpoint: &Endpoint,

lib/llm/src/entrypoint/input/common.rs

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 use std::pin::Pin;
+use std::time::Duration;
 
 use crate::{
     backend::{Backend, ExecutionContext},
@@ -28,6 +29,7 @@ use crate::{
 };
 
 use anyhow::Context as _;
+use dynamo_kv_router::config::min_initial_workers_from_env;
 use dynamo_runtime::{
     DistributedRuntime,
     component::Client,
@@ -47,6 +49,45 @@ pub struct PreparedEngine {
     pub request_template: Option<RequestTemplate>,
 }
 
+async fn wait_for_min_initial_workers(
+    client: &Client,
+    min_initial_workers: usize,
+) -> anyhow::Result<()> {
+    if min_initial_workers == 0 {
+        return Ok(());
+    }
+
+    if min_initial_workers == 1 {
+        client.wait_for_instances().await?;
+        return Ok(());
+    }
+
+    let mut watcher = client.instance_avail_watcher();
+    loop {
+        let available = watcher.borrow_and_update().len();
+        if available >= min_initial_workers {
+            return Ok(());
+        }
+
+        tokio::time::timeout(Duration::from_secs(120), watcher.changed())
+            .await
+            .map_err(|_| {
+                anyhow::anyhow!(
+                    "timed out waiting for {} initial workers for endpoint {}",
+                    min_initial_workers,
+                    client.endpoint.id()
+                )
+            })?
+            .map_err(|_| {
+                anyhow::anyhow!(
+                    "instance watcher closed before {} workers appeared for endpoint {}",
+                    min_initial_workers,
+                    client.endpoint.id()
+                )
+            })?;
+    }
+}
+
 impl PreparedEngine {
     pub fn has_tokenizer(&self) -> bool {
         if let Some(card) = self.card.as_ref() {
@@ -254,6 +295,7 @@ where
     let preprocessor_op = preprocessor.into_operator();
     let backend = Backend::from_tokenizer(tokenizer).into_operator();
     let migration = Migration::from_mdc(card, migration_limit, metrics).into_operator();
+    let min_initial_workers = min_initial_workers_from_env()?;
 
     // For KV routing, use the client from the chooser to ensure shared state
     let router_client = if router_mode == RouterMode::KV {
@@ -265,6 +307,8 @@ where
         client.clone()
     };
 
+    wait_for_min_initial_workers(&router_client, min_initial_workers).await?;
+
     // Get threshold value and wrap monitor for PushRouter
     // Note: PushRouter uses active_decode_blocks_threshold for its internal logic
     let threshold_value = worker_monitor

lib/llm/src/kv_router.rs

@@ -5,7 +5,7 @@ use std::time::Instant;
 
 use anyhow::Result;
 use dynamo_kv_router::{
-    config::{KvRouterConfig, RouterConfigOverride},
+    config::{KvRouterConfig, RouterConfigOverride, min_initial_workers_from_env},
     indexer::KvRouterError,
     protocols::KV_EVENT_SUBJECT,
     protocols::{
@@ -126,7 +126,7 @@ where
     pub async fn new(
         endpoint: Endpoint,
         client: Client,
-        mut workers_with_configs: RuntimeConfigWatch,
+        workers_with_configs: RuntimeConfigWatch,
         block_size: u32,
         selector: Sel,
         kv_router_config: Option<KvRouterConfig>,
@@ -138,17 +138,19 @@ where
         kv_router_config.validate()?;
         let component = endpoint.component();
         let cancellation_token = component.drt().primary_token();
+        let min_initial_workers = min_initial_workers_from_env()?;
 
         let indexer = Indexer::new(component, &kv_router_config, block_size, model_name).await?;
 
-        if !kv_router_config.skip_initial_worker_wait {
-            let _ = workers_with_configs
-                .wait_for(|m| m.len() >= kv_router_config.min_initial_workers)
+        if min_initial_workers > 0 && !kv_router_config.skip_initial_worker_wait {
+            let mut startup_watch = workers_with_configs.clone();
+            let _ = startup_watch
+                .wait_for(|m| m.len() >= min_initial_workers)
                 .await
                 .map_err(|_| {
                     anyhow::anyhow!(
                         "runtime config watch closed before {} workers appeared",
-                        kv_router_config.min_initial_workers
+                        min_initial_workers
                     )
                 })?;
         }

lib/llm/src/kv_router/sequence.rs

@@ -217,8 +217,7 @@ mod tests {
 
         tokio::time::sleep(tokio::time::Duration::from_millis(200)).await;
 
-        seq_manager_1
-            .add_request(SequenceRequest {
+        seq_manager_1.add_request(SequenceRequest {
             request_id: "request_0".to_string(),
             token_sequence: Some(vec![0, 1, 2]),
             isl: 12,
@@ -227,11 +226,9 @@ mod tests {
             expected_output_tokens: None,
             worker: WorkerWithDpRank::new(0, 0),
             lora_name: None,
-            })
-            .await?;
+        })?;
 
-        seq_manager_1
-            .add_request(SequenceRequest {
+        seq_manager_1.add_request(SequenceRequest {
             request_id: "request_1".to_string(),
             token_sequence: Some(vec![3, 4]),
             isl: 8,
@@ -240,11 +237,9 @@ mod tests {
             expected_output_tokens: None,
             worker: WorkerWithDpRank::new(0, 1),
             lora_name: None,
-            })
-            .await?;
+        })?;
 
-        seq_manager_2
-            .add_request(SequenceRequest {
+        seq_manager_2.add_request(SequenceRequest {
             request_id: "request_2".to_string(),
             token_sequence: Some(vec![0, 1, 2, 3]),
             isl: 16,
@@ -253,8 +248,7 @@ mod tests {
             expected_output_tokens: None,
             worker: WorkerWithDpRank::new(1, 0),
             lora_name: None,
-            })
-            .await?;
+        })?;
 
         tokio::time::sleep(tokio::time::Duration::from_millis(300)).await;
 
@@ -290,10 +284,10 @@ mod tests {
             "Worker 1 dp_rank 0 should have 16 active tokens (from request_2 added by seq_manager_2)"
         );
 
-        seq_manager_1.free(&"request_2".to_string()).await?;
+        seq_manager_1.free(&"request_2".to_string())?;
 
-        seq_manager_2.free(&"request_0".to_string()).await?;
-        seq_manager_2.free(&"request_1".to_string()).await?;
+        seq_manager_2.free(&"request_0".to_string())?;
+        seq_manager_2.free(&"request_1".to_string())?;
 
         tokio::time::sleep(tokio::time::Duration::from_millis(300)).await;
 
@@ -370,8 +364,7 @@ mod tests {
 
         tokio::time::sleep(tokio::time::Duration::from_millis(200)).await;
 
-        seq_manager_1
-            .add_request(SequenceRequest {
+        seq_manager_1.add_request(SequenceRequest {
             request_id: "request_0".to_string(),
             token_sequence: None,
             isl: 12,
@@ -380,11 +373,9 @@ mod tests {
             expected_output_tokens: None,
             worker: WorkerWithDpRank::from_worker_id(0),
             lora_name: None,
-            })
-            .await?;
+        })?;
 
-        seq_manager_1
-            .add_request(SequenceRequest {
+        seq_manager_1.add_request(SequenceRequest {
             request_id: "request_1".to_string(),
             token_sequence: None,
             isl: 8,
@@ -393,11 +384,9 @@ mod tests {
             expected_output_tokens: None,
             worker: WorkerWithDpRank::from_worker_id(1),
             lora_name: None,
-            })
-            .await?;
+        })?;
 
-        seq_manager_2
-            .add_request(SequenceRequest {
+        seq_manager_2.add_request(SequenceRequest {
             request_id: "request_2".to_string(),
             token_sequence: None,
             isl: 16,
@@ -406,8 +395,7 @@ mod tests {
             expected_output_tokens: None,
             worker: WorkerWithDpRank::from_worker_id(2),
             lora_name: None,
-            })
-            .await?;
+        })?;
 
         tokio::time::sleep(tokio::time::Duration::from_millis(300)).await;
 
@@ -430,19 +418,13 @@ mod tests {
             "Worker 2 should have 16 active tokens (from request_2 added by seq_manager_2)"
         );
 
-        seq_manager_1
-            .mark_prefill_completed(&"request_2".to_string())
-            .await?;
-        seq_manager_1.free(&"request_2".to_string()).await?;
+        seq_manager_1.mark_prefill_completed(&"request_2".to_string())?;
+        seq_manager_1.free(&"request_2".to_string())?;
 
-        seq_manager_2
-            .mark_prefill_completed(&"request_0".to_string())
-            .await?;
-        seq_manager_2
-            .mark_prefill_completed(&"request_1".to_string())
-            .await?;
-        seq_manager_2.free(&"request_0".to_string()).await?;
-        seq_manager_2.free(&"request_1".to_string()).await?;
+        seq_manager_2.mark_prefill_completed(&"request_0".to_string())?;
+        seq_manager_2.mark_prefill_completed(&"request_1".to_string())?;
+        seq_manager_2.free(&"request_0".to_string())?;
+        seq_manager_2.free(&"request_1".to_string())?;
 
         tokio::time::sleep(tokio::time::Duration::from_millis(300)).await;
 

lib/llm/src/mocker.rs

@@ -396,7 +396,7 @@ impl MockEngine {
         let mut senders = Vec::with_capacity(args.dp_size as usize);
 
         for dp_rank in 0..args.dp_size {
-            let (output_tx, mut output_rx) = mpsc::unbounded_channel::<OutputSignal>();
+            let (output_tx, mut output_rx) = mpsc::unbounded_channel::<Vec<OutputSignal>>();
 
             let (kv_event_publishers, relay_publisher): (
                 KvEventPublishers,
@@ -499,14 +499,16 @@ impl MockEngine {
                 loop {
                     tokio::select! {
                         signal_result = output_rx.recv() => {
-                            let Some(signal) = signal_result else {
+                            let Some(output_batch) = signal_result else {
                                 break; // Channel closed
                             };
 
+                            for signal in output_batch {
                                 if let Some(request_tx) = active_requests_clone.get(&signal.uuid) {
                                     let _ = request_tx.send(signal);
                                 }
                             }
+                        }
                         _ = cancel_token_cloned.cancelled() => {
                             tracing::info!("Scheduler output task cancelled, clearing active requests");
                             active_requests_clone.clear();