[mm] refactor mm code for rust tokenizer manager (#34660)

Co-authored-by: Rain Jiang <rain-jiang@outlook.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

python/sglang/srt/rust_server/multimodal.py

@@ -23,7 +23,7 @@ class RustMmSpec(msgspec.Struct, frozen=True, kw_only=True):
     consumed by the Rust worker pool (as the typed extension ``MmSpec``, see
     :meth:`RustServer._build_mm_spec`), the ``_multimodal`` parity API
     (:meth:`rust_json`) and the drain adapter
-    (:meth:`RustMmProcessor.build_output`)."""
+    (:meth:`RustMmProcessor.wrap_encoded`)."""
 
     family: str
     feature_shm: bool
@@ -119,7 +119,7 @@ class RustMmProcessor:
     TokenizerManager would build — not to process requests (the Rust worker pool
     does that, GIL-free) but as the source of truth
     :meth:`resolve_spec` resolves the pipeline parameters from. At drain
-    time :meth:`build_output` wraps the Rust-produced buffers into the
+    time :meth:`wrap_encoded` wraps the Rust-produced buffers into the
     scheduler's ``MultimodalProcessorOutput``.
 
     There is no Python fallback: a model without a Rust MM spec fails at launch,
@@ -174,17 +174,17 @@ class RustMmProcessor:
         )
         if family is None:
             return None
-        ip = getattr(self._processor, "image_processor", None)
-        resample = family.image_processors.get(type(ip).__name__)
+        image_processor = getattr(self._processor, "image_processor", None)
+        resample = family.image_processors.get(type(image_processor).__name__)
         if resample is None:
             return None
         # The Rust pipeline always resizes, rescales by 1/255 and normalizes;
         # Rust's fused normalize constants assume that factor. Anything else
         # would silently produce different features.
         stages = ("do_resize", "do_rescale", "do_normalize")
-        if not all(getattr(ip, stage, True) for stage in stages):
+        if not all(getattr(image_processor, stage, True) for stage in stages):
             return None
-        if getattr(ip, "rescale_factor", None) != 1 / 255:
+        if getattr(image_processor, "rescale_factor", None) != 1 / 255:
             return None
 
         # `--mm-process-config {"image": {...}}`: only pixel-limit overrides are
@@ -193,25 +193,27 @@ class RustMmProcessor:
         if not set(image_overrides) <= {"min_pixels", "max_pixels"}:
             return None
 
-        size = getattr(ip, "size", None) or {}
+        size = getattr(image_processor, "size", None) or {}
         min_pixels = image_overrides.get(
-            "min_pixels", getattr(ip, "min_pixels", None) or size.get("shortest_edge")
+            "min_pixels",
+            getattr(image_processor, "min_pixels", None) or size.get("shortest_edge"),
         )
         max_pixels = image_overrides.get(
-            "max_pixels", getattr(ip, "max_pixels", None) or size.get("longest_edge")
+            "max_pixels",
+            getattr(image_processor, "max_pixels", None) or size.get("longest_edge"),
         )
         try:
             spec = RustMmSpec(
                 family=family.name,
                 feature_shm=self._use_feature_shm(),
                 image_token_id=hf_config.image_token_id,
-                patch_size=ip.patch_size,
-                merge_size=ip.merge_size,
-                temporal_patch_size=ip.temporal_patch_size,
+                patch_size=image_processor.patch_size,
+                merge_size=image_processor.merge_size,
+                temporal_patch_size=image_processor.temporal_patch_size,
                 min_pixels=int(min_pixels),
                 max_pixels=int(max_pixels),
-                image_mean=tuple(float(x) for x in ip.image_mean),
-                image_std=tuple(float(x) for x in ip.image_std),
+                image_mean=tuple(float(x) for x in image_processor.image_mean),
+                image_std=tuple(float(x) for x in image_processor.image_std),
                 resample=resample,
                 vision_start_token_id=getattr(hf_config, "vision_start_token_id", None),
                 vision_end_token_id=getattr(hf_config, "vision_end_token_id", None),
@@ -247,10 +249,11 @@ class RustMmProcessor:
         )
 
     @staticmethod
-    def build_output(spec: RustMmSpec, entry):
-        """Drain-time adapter: wrap the Rust-produced buffers of one ``MmEncodeResult``
-        into the scheduler's ``MultimodalProcessorOutput``. Wrapping only — load,
-        resize, patchify, token expansion and M-RoPE all ran in Rust.
+    def wrap_encoded(spec: RustMmSpec, encoded):
+        """Drain-time adapter: wrap the Rust-produced buffers of one
+        ``MmEncodedResult`` into the scheduler's ``MultimodalProcessorOutput``.
+        Wrapping only — load, resize, patchify, token expansion and M-RoPE all
+        ran in Rust.
 
         Runs on the scheduler loop, so it must stay copy-free *and* hash-free:
         ``take_mm_result``'s numpy arrays own the Rust buffers, ``torch.from_numpy`` just
@@ -267,13 +270,13 @@ class RustMmProcessor:
             MultimodalProcessorOutput,
         )
 
-        shm_names = entry.shm_names
+        shm_names = encoded.shm_names
         if shm_names is None:
-            features = torch.from_numpy(entry.features.reshape(-1, spec.feature_dim))
+            features = torch.from_numpy(encoded.features.reshape(-1, spec.feature_dim))
         items = []
         row = 0
         for index, ((t, h, w), item_hash, offset) in enumerate(
-            zip(entry.grids, entry.hashes, entry.offsets)
+            zip(encoded.grids, encoded.hashes, encoded.offsets)
         ):
             n = t * h * w
             if shm_names is None:
@@ -314,6 +317,8 @@ class RustMmProcessor:
             im_start_id=spec.vision_start_token_id,
             im_end_id=spec.vision_end_token_id,
             video_token_id=spec.video_token_id,
-            mrope_positions=torch.from_numpy(entry.mrope.reshape(3, -1)),
-            mrope_position_delta=torch.tensor([[entry.mrope_delta]], dtype=torch.long),
+            mrope_positions=torch.from_numpy(encoded.mrope.reshape(3, -1)),
+            mrope_position_delta=torch.tensor(
+                [[encoded.mrope_delta]], dtype=torch.long
+            ),
         )

python/sglang/srt/rust_server/server.py

@@ -205,14 +205,13 @@ class RustServer:
                 obj.input_ids = ids
                 pos += nbytes
             if self.mm_spec is not None and isinstance(obj, TokenizedGenerateReqInput):
-                # The buffers rode the Rust sidecar, parked before the ring push;
-                # wrapping them into tensors is the only Python step of the Rust
-                # path. `None` for a text-only request on a multimodal model.
-                mm_result = self.server.take_mm_result(obj.rid)
-                if mm_result is not None:
-                    obj.mm_inputs = RustMmProcessor.build_output(
-                        self.mm_spec, mm_result
-                    )
+                # The buffers were parked in the Rust result store before the
+                # ring push; wrapping them into tensors is the only Python step
+                # of the Rust path. `None` for a text-only request on a
+                # multimodal model.
+                encoded = self.server.take_mm_result(obj.rid)
+                if encoded is not None:
+                    obj.mm_inputs = RustMmProcessor.wrap_encoded(self.mm_spec, encoded)
             out.append(obj)
         return out
 

rust/sglang-mm/src/qwen_vl/mod.rs

@@ -344,31 +344,36 @@ pub fn mrope_image_only(
 
 /// The qwen scheduler-drain shape, extracted from the generic driver
 /// [`Output`](crate::driver::Output). Shared by `sglang-server`'s MM worker
-/// and the parity binding so the mapping can't drift; replaced by a generic
-/// named-tensor handoff once a second family needs a different shape.
-pub struct QwenDrain {
+/// and the parity binding so the mapping can't drift. TODO(mm-families):
+/// replace with a generic named-tensor handoff once a second family needs a
+/// different shape.
+pub struct QwenPackedOutput {
     pub input_ids: Vec<i32>,
-    /// All items' `pixel_values`, concatenated in prompt order.
+    /// All items' `pixel_values`, concatenated in prompt order; flattened
+    /// `[Σ t·h·w, 3·temporal_patch_size·patch_size²]`.
     pub features: Vec<f32>,
+    /// Per item `[t, h, w]` patch grid.
     pub grids: Vec<[u32; 3]>,
     pub hashes: Vec<u64>,
+    /// Per item inclusive token range in `input_ids`.
     pub offsets: Vec<(u32, u32)>,
+    /// Flattened row-major `[3, input_len]` M-RoPE positions.
     pub mrope: Vec<i64>,
     pub mrope_delta: i64,
 }
 
-pub fn pack_drain(output: crate::driver::Output) -> Result<QwenDrain, String> {
+pub fn pack_output(output: crate::driver::Output) -> Result<QwenPackedOutput, String> {
     use crate::pipeline::PositionOutput;
 
     let PositionOutput::MRope { positions, delta } = output.positions else {
-        return Err("qwen_vl drain: expected M-RoPE positions".into());
+        return Err("qwen_vl pack: expected M-RoPE positions".into());
     };
     let mut features = Vec::new();
     let mut grids = Vec::with_capacity(output.items.len());
     let mut hashes = Vec::with_capacity(output.items.len());
     for item in output.items {
         let TensorData::F32(pixel_values) = item.feature.data else {
-            return Err("qwen_vl drain: expected f32 feature".into());
+            return Err("qwen_vl pack: expected f32 feature".into());
         };
         features.extend(pixel_values);
         let grid = item
@@ -378,11 +383,11 @@ pub fn pack_drain(output: crate::driver::Output) -> Result<QwenDrain, String> {
                 ("image_grid_thw", TensorData::I64(v)) => Some(v),
                 _ => None,
             })
-            .ok_or("qwen_vl drain: missing image_grid_thw")?;
+            .ok_or("qwen_vl pack: missing image_grid_thw")?;
         grids.push([grid[0] as u32, grid[1] as u32, grid[2] as u32]);
         hashes.push(item.hash);
     }
-    Ok(QwenDrain {
+    Ok(QwenPackedOutput {
         input_ids: output.input_ids,
         features,
         grids,
@@ -504,23 +509,27 @@ mod python {
             input_ids,
             images,
         };
-        let drain = py
+        let packed = py
             .detach(move || {
                 let family = crate::registry::pipeline_from_spec(&spec_json)?;
                 let output = crate::driver::process(family.as_ref(), input, |_| {
                     Err("native parity API requires input_ids".into())
                 })?;
-                pack_drain(output)
+                pack_output(output)
             })
             .map_err(PyValueError::new_err)?;
         Ok((
-            drain.input_ids,
-            drain.features.into_pyarray(py),
-            drain.grids.into_iter().map(|[t, h, w]| (t, h, w)).collect(),
-            drain.hashes,
-            drain.offsets,
-            drain.mrope.into_pyarray(py),
-            drain.mrope_delta,
+            packed.input_ids,
+            packed.features.into_pyarray(py),
+            packed
+                .grids
+                .into_iter()
+                .map(|[t, h, w]| (t, h, w))
+                .collect(),
+            packed.hashes,
+            packed.offsets,
+            packed.mrope.into_pyarray(py),
+            packed.mrope_delta,
         ))
     }
 

rust/sglang-server/src/lib.rs

@@ -6,7 +6,7 @@
 //! ([`ServerArgs`] and its parts, constructed by keyword from Python; their
 //! `#[pyclass]`es and constructors live in `message::config`), [`Server`]
 //! (boot, `recv_requests`/`wait_request`, `push_*`, MM handoff, shutdown),
-//! [`RequestBatch`] and [`MmEncodeResult`]. Everything behind that boundary —
+//! [`RequestBatch`] and [`MmEncodedResult`]. Everything behind that boundary —
 //! receiving requests, encoding multimodal inputs, tokenizing, detokenizing,
 //! SSE streaming, and so on — is implemented purely in Rust and never touches
 //! a `PyObject`.
@@ -29,10 +29,10 @@ use crate::utils::startup::{listen_addr, value_error};
 use crate::utils::{logging, runtime};
 
 /// One drained MM result (see [`Server::take_mm_result`]), consumed by
-/// `RustMmProcessor.build_output` to build the scheduler's
+/// `RustMmProcessor.wrap_encoded` to build the scheduler's
 /// `MultimodalProcessorOutput`.
 #[pyclass(frozen, get_all)]
-struct MmEncodeResult {
+struct MmEncodedResult {
     // General fields.
     /// All items' `pixel_values` concatenated as flat `f32` with logical shape
     /// `[sum(t*h*w), feature_dim]`; present on the inline (single-rank) path.
@@ -199,14 +199,9 @@ impl Server {
     /// in Rust and parked for [`Server::take_mm_result`]; anything the pipeline
     /// cannot serve is rejected back to the client — there is no Python fallback.
     fn start_mm_workers(&self, spec: MmSpec, workers: usize) -> PyResult<()> {
-        let ctx = multi_modality::worker::Context::new(
-            spec,
-            self.rt.tokenizer.clone(),
-            self.rt.mm_sidecar.clone(),
-        )
-        .map_err(|e| value_error("mm spec", e))?;
-        self.rt.spawn_mm_pool(workers, std::sync::Arc::new(ctx));
-        Ok(())
+        self.rt
+            .start_mm_workers(spec, workers)
+            .map_err(|e| value_error("mm spec", e))
     }
 
     /// Pop the MM result for `rid` — parked strictly before the request reached
@@ -217,22 +212,22 @@ impl Server {
     /// Runs on the scheduler loop between decode steps, so any per-byte work
     /// here — memcpy or hashing, tens of MB per image-heavy request — would
     /// stall every running request's ITL. Hence the worker-precomputed `hashes`.
-    fn take_mm_result(&self, py: Python<'_>, rid: &str) -> Option<MmEncodeResult> {
+    fn take_mm_result(&self, py: Python<'_>, rid: &str) -> Option<MmEncodedResult> {
         use numpy::IntoPyArray;
 
-        let res = self.rt.mm_sidecar.take(rid)?;
+        let res = self.rt.mm_results.take(rid)?;
         let (features, shm_names) = match res.features {
-            multi_modality::sidecar::FeatureStore::Inline(v) => {
+            multi_modality::result_store::FeatureStore::Inline(v) => {
                 (Some(v.into_pyarray(py).unbind()), None)
             }
             // The segments — and the duty to unlink — move to Python here;
             // `materialize()` unlinks after the post-broadcast clone on each rank.
-            multi_modality::sidecar::FeatureStore::Shm(segments) => (
+            multi_modality::result_store::FeatureStore::Shm(segments) => (
                 None,
                 Some(segments.into_iter().map(|s| s.into_name()).collect()),
             ),
         };
-        Some(MmEncodeResult {
+        Some(MmEncodedResult {
             features,
             shm_names,
             grids: res.grids.iter().map(|g| (g[0], g[1], g[2])).collect(),
@@ -276,6 +271,6 @@ fn _server(m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_class::<MmSpec>()?;
     m.add_class::<Server>()?;
     m.add_class::<RequestBatch>()?;
-    m.add_class::<MmEncodeResult>()?;
+    m.add_class::<MmEncodedResult>()?;
     Ok(())
 }

rust/sglang-server/src/multi_modality.rs

@@ -1,6 +1,6 @@
 //! Multimodal worker pool.
 
 pub mod payload;
+pub mod result_store;
 mod shm;
-pub mod sidecar;
 pub mod worker;

rust/sglang-server/src/multi_modality/result_store.rs

@@ -7,17 +7,22 @@ use std::sync::{Arc, Mutex};
 use super::shm::{ShmSegment, shm_name};
 
 /// One parked result: the buffers the drain-time Python adapter needs (the
-/// expanded `input_ids` travel separately, via `TmEvent::MmEncoded`). The qwen
-/// drain shape (`sglang_mm::qwen_vl::pack_drain`); generalizes to a
-/// named-tensor handoff once a family needs a different one.
+/// expanded `input_ids` travel separately, via `TmEvent::MmEncoded`).
+///
+/// TODO(mm-families): these fields are the shape the only current family
+/// (qwen_vl) produces; generalize to a named-tensor handoff when a family
+/// needs a different one.
 ///
 /// Constructed from outside the module only by tests; the worker parks every
 /// real entry itself.
-pub struct MmSidecarEntry {
+pub struct MmEncodedEntry {
     pub features: FeatureStore,
+    /// Per item `[t, h, w]` patch grid.
     pub grids: Vec<[u32; 3]>,
     pub hashes: Vec<u64>,
+    /// Per item inclusive token range in the expanded prompt.
     pub offsets: Vec<(u32, u32)>,
+    /// Flattened row-major `[3, input_len]` M-RoPE positions.
     pub mrope: Vec<i64>,
     pub mrope_delta: i64,
 }
@@ -37,13 +42,13 @@ pub enum FeatureStore {
 /// strictly before `MmEncoded`, [`take`](Self::take) at the drain,
 /// [`purge`](Self::purge) for requests that die while parked.
 #[derive(Clone, Default)]
-pub struct Sidecar(Arc<Mutex<HashMap<String, MmSidecarEntry>>>);
+pub struct MmResultStore(Arc<Mutex<HashMap<String, MmEncodedEntry>>>);
 
-impl Sidecar {
-    pub fn park(&self, rid: String, entry: MmSidecarEntry) {
+impl MmResultStore {
+    pub fn park(&self, rid: String, entry: MmEncodedEntry) {
         self.0.lock().unwrap().insert(rid, entry);
     }
-    pub fn take(&self, rid: &str) -> Option<MmSidecarEntry> {
+    pub fn take(&self, rid: &str) -> Option<MmEncodedEntry> {
         self.0.lock().unwrap().remove(rid)
     }
     pub fn purge(&self, rid: &str) {

rust/sglang-server/src/multi_modality/shm.rs

@@ -86,7 +86,7 @@ pub(super) fn shm_name(item: usize) -> String {
     format!("sglmm-{}-{n}-{item}", std::process::id())
 }
 
-/// Test helper shared with the sidecar's parking tests.
+/// Test helper shared with the result store's parking tests.
 #[cfg(test)]
 pub(super) fn shm_path(name: &str) -> std::path::PathBuf {
     std::path::Path::new("/dev/shm").join(name)

rust/sglang-server/src/multi_modality/worker.rs

@@ -3,7 +3,7 @@
 
 use std::sync::Arc;
 
-use super::sidecar::{FeatureStore, MmSidecarEntry, Sidecar, park_features_in_shm};
+use super::result_store::{FeatureStore, MmEncodedEntry, MmResultStore, park_features_in_shm};
 use crate::message::config::MmSpec;
 use crate::message::ids::Rid;
 use crate::message::request::MmRequest;
@@ -46,27 +46,27 @@ fn parse_caller_hash(entry: &str) -> Option<u64> {
 }
 
 /// Shared state of the mm path, built once at `start_mm_workers`.
-pub struct Context {
+pub struct MmContext {
     pub family: Box<dyn sglang_mm::pipeline::MmFamilyProcessor>,
     /// `None` under `skip_tokenizer_init` (requests must carry `input_ids`).
     pub tokenizer: Option<Arc<dyn TextTokenizer>>,
-    pub sidecar: Sidecar,
+    pub results: MmResultStore,
     /// Park feature buffers in POSIX shm. Set by the Python launcher
     /// (`RustMmProcessor._use_feature_shm`) exactly when the scheduler broadcasts
     /// across TP ranks and will unwrap `ShmPointerMMData`.
     pub feature_shm: bool,
 }
 
-impl Context {
+impl MmContext {
     pub fn new(
         spec: MmSpec,
         tokenizer: Option<Arc<dyn TextTokenizer>>,
-        sidecar: Sidecar,
+        results: MmResultStore,
     ) -> Result<Self, String> {
         Ok(Self {
             family: sglang_mm::registry::build_pipeline(spec.pipeline)?,
             tokenizer,
-            sidecar,
+            results,
             feature_shm: spec.feature_shm,
         })
     }
@@ -75,7 +75,7 @@ impl Context {
 /// Run the pipeline for one request. `Ok` returns the final expanded ids, the
 /// buffers already parked; `Err` rejects the request back to the client.
 fn process(
-    ctx: &Context,
+    ctx: &MmContext,
     rid: &Rid,
     mut work: crate::message::request::MmWorkItem,
 ) -> Result<Vec<i32>, String> {
@@ -87,42 +87,60 @@ fn process(
         })?;
         tokenizer.encode(text).map_err(|error| error.to_string())
     })?;
-    let mut drain = sglang_mm::qwen_vl::pack_drain(output)?;
-    apply_caller_hashes(&mut drain.hashes, &caller_hashes);
+    // TODO(mm-families): the one family-specific call in this worker — dispatch
+    // on the spec's `family` (as `registry::build_pipeline` does) once a
+    // second family lands.
+    let mut packed = sglang_mm::qwen_vl::pack_output(output)?;
+    apply_caller_hashes(&mut packed.hashes, &caller_hashes);
     let features = if ctx.feature_shm {
-        park_features_in_shm(&drain.features, &drain.grids)
+        park_features_in_shm(&packed.features, &packed.grids)
     } else {
-        FeatureStore::Inline(drain.features)
+        FeatureStore::Inline(packed.features)
     };
-    ctx.sidecar.park(
+    ctx.results.park(
         rid.as_str().to_owned(),
-        MmSidecarEntry {
+        MmEncodedEntry {
             features,
-            grids: drain.grids,
-            hashes: drain.hashes,
-            offsets: drain.offsets,
-            mrope: drain.mrope,
-            mrope_delta: drain.mrope_delta,
+            grids: packed.grids,
+            hashes: packed.hashes,
+            offsets: packed.offsets,
+            mrope: packed.mrope,
+            mrope_delta: packed.mrope_delta,
         },
     );
-    Ok(drain.input_ids)
+    Ok(packed.input_ids)
 }
 
-/// One MM worker, spawned via `Runtime::spawn_mm_pool` (which owns the
+/// Boot-time wiring of the MM path, held privately by the `Runtime` for the
+/// late pool spawn (`Runtime::start_mm_workers`, once Python has resolved
+/// the spec).
+pub struct MmWiring {
+    /// Requests parked in `Encoding`, drained by the worker pool. Stays empty
+    /// for non-multimodal models — nothing routes to it.
+    pub mm_rx: flume::Receiver<MmRequest>,
+    /// Back-channel for the workers' `MmEncoded` / `MmFailed` into the
+    /// to-scheduler loop.
+    pub tm_tx: flume::Sender<TmEvent>,
+    /// The loaded tokenizer, shared with the tokenizer pool (`None` under
+    /// `skip_tokenizer_init`).
+    pub tokenizer: Option<Arc<dyn TextTokenizer>>,
+}
+
+/// One MM worker, spawned via `Runtime::start_mm_workers` (which owns the
 /// pinning policy for this pool — see its docs).
 pub struct MmWorker {
-    rx: flume::Receiver<MmRequest>,
-    tm: flume::Sender<TmEvent>,
-    ctx: Arc<Context>,
+    mm_rx: flume::Receiver<MmRequest>,
+    tm_tx: flume::Sender<TmEvent>,
+    ctx: Arc<MmContext>,
 }
 
 impl MmWorker {
     pub fn new(
-        rx: flume::Receiver<MmRequest>,
-        tm: flume::Sender<TmEvent>,
-        ctx: Arc<Context>,
+        mm_rx: flume::Receiver<MmRequest>,
+        tm_tx: flume::Sender<TmEvent>,
+        ctx: Arc<MmContext>,
     ) -> Self {
-        Self { rx, tm, ctx }
+        Self { mm_rx, tm_tx, ctx }
     }
 }
 
@@ -131,7 +149,7 @@ impl Runnable for MmWorker {
     /// shutdown). One request at a time, so the pool size bounds MM
     /// concurrency; an error rejects the request back to the client.
     fn run(self) {
-        while let Ok(req) = self.rx.recv() {
+        while let Ok(req) = self.mm_rx.recv() {
             let rid = req.rid;
             let event = match process(&self.ctx, &rid, req.work) {
                 Ok(input_ids) => {
@@ -143,7 +161,7 @@ impl Runnable for MmWorker {
                     TmEvent::MmFailed { rid, message }
                 }
             };
-            if self.tm.send(event).is_err() {
+            if self.tm_tx.send(event).is_err() {
                 return; // to-scheduler gone: shutdown
             }
         }

rust/sglang-server/src/tokenizer_manager/to_scheduler.rs

@@ -11,7 +11,7 @@ use crate::message::request::{MmRequest, Request, RequestKind, SchedulerRequest}
 use crate::message::response::ResponseItem;
 use crate::runtime::Runnable;
 use crate::tokenizer_manager::channel::ToSchedulerTx;
-pub use crate::tokenizer_manager::to_scheduler_types::{Limits, Mm};
+pub use crate::tokenizer_manager::to_scheduler_types::{Limits, MmDispatch};
 use crate::tokenizer_manager::to_scheduler_validation::{
     check_total_tokens, validate, validate_input_ids,
 };
@@ -36,7 +36,7 @@ pub struct Intake {
     senders: Senders,
     to_scheduler_tx: ToSchedulerTx,
     limits: Limits,
-    mm: Mm,
+    mm: MmDispatch,
     /// Requests parked in `Encoding` while an MM worker processes their media;
     /// resumed by `MmEncoded` / `MmFailed`. Only this thread touches it, so no
     /// lock.
@@ -51,7 +51,7 @@ impl Intake {
         senders: Senders,
         to_scheduler_tx: ToSchedulerTx,
         limits: Limits,
-        mm: Mm,
+        mm: MmDispatch,
         shutdown: flume::Receiver<()>,
     ) -> Self {
         Self {
@@ -126,7 +126,7 @@ impl Intake {
         }
         // A rejected request never reaches the scheduler drain, so purge any
         // parked MM result (no-op for the common non-mm request).
-        self.mm.sidecar.purge(req.rid.as_str());
+        self.mm.results.purge(req.rid.as_str());
         let _ = req.state.apply(Event::Error(err.clone()));
         let _ = req.sink.try_send(ResponseItem::Error(err)); // client may be gone
         if registered {
@@ -402,7 +402,7 @@ impl Intake {
         let Some(mut req) = self.pending_mm.remove(&rid) else {
             tracing::debug!(rid = %rid, "mm result for unknown/finished request; dropped");
             // It will never reach the scheduler drain, so purge or leak.
-            self.mm.sidecar.purge(rid.as_str());
+            self.mm.results.purge(rid.as_str());
             return;
         };
         if let RequestKind::Generate(g) = &mut req.kind {
@@ -432,8 +432,8 @@ impl Intake {
     /// ([`Rid::from_client`]), so no later request can ever answer to it.
     ///
     /// A request parked in `pending_mm` is cancelled here, so the worker's late
-    /// result lands in `on_mm_encoded`'s no-entry branch and purges the sidecar —
-    /// no generation runs for output nobody will read.
+    /// result lands in `on_mm_encoded`'s no-entry branch and purges the parked
+    /// result — no generation runs for output nobody will read.
     fn on_abort(&mut self, source: AbortSource) {
         let rid = source.rid().clone();
         if self.pending_mm.remove(&rid).is_some() {

rust/sglang-server/src/tokenizer_manager/to_scheduler_tests.rs

@@ -84,12 +84,12 @@ fn make_intake_inner(
     (intake, detok_rx, consumer, tm_tx, mm_rx)
 }
 
-/// An [`Mm`] over `tx` with a fresh sidecar.
-fn test_mm(tx: flume::Sender<MmRequest>, enabled: bool) -> Mm {
-    Mm {
+/// An [`MmDispatch`] over `tx` with a fresh result store.
+fn test_mm(tx: flume::Sender<MmRequest>, enabled: bool) -> MmDispatch {
+    MmDispatch {
         enabled,
         tx,
-        sidecar: Default::default(),
+        results: Default::default(),
     }
 }
 
@@ -781,7 +781,7 @@ fn mm_generate_req(rid: &str) -> Request {
 
 /// An abort while the request is parked for MM cancels it: the pending
 /// entry is removed, the worker's late result is dropped, and its parked
-/// sidecar entry is purged — no scheduler work runs for a dead client.
+/// result-store entry is purged — no scheduler work runs for a dead client.
 #[test]
 fn abort_cancels_parked_mm_request() {
     let (mut intake, _detok_rx, consumer, _tm_tx, mm_rx) = make_intake();
@@ -789,10 +789,10 @@ fn abort_cancels_parked_mm_request() {
     mm_rx.try_recv().expect("parked to mm pool");
 
     // The worker parks its result, as it always does before MmEncoded.
-    intake.mm.sidecar.park(
+    intake.mm.results.park(
         "mm-gone".into(),
-        crate::multi_modality::sidecar::MmSidecarEntry {
-            features: crate::multi_modality::sidecar::FeatureStore::Inline(vec![]),
+        crate::multi_modality::result_store::MmEncodedEntry {
+            features: crate::multi_modality::result_store::FeatureStore::Inline(vec![]),
             grids: vec![],
             hashes: vec![],
             offsets: vec![],
@@ -803,13 +803,13 @@ fn abort_cancels_parked_mm_request() {
     intake.on_abort(AbortSource::Guard("mm-gone".to_string().into()));
     assert_eq!(consumer.drain(16).headers.len(), 1, "only the AbortReq");
 
-    // The late result must be dropped, not queued, and the sidecar purged.
+    // The late result must be dropped, not queued, and the parked result purged.
     intake.on_mm_encoded("mm-gone".to_string().into(), vec![5, 6]);
     assert!(
         consumer.drain(16).headers.is_empty(),
         "cancelled, not queued"
     );
-    assert!(intake.mm.sidecar.take("mm-gone").is_none(), "entry purged");
+    assert!(intake.mm.results.take("mm-gone").is_none(), "entry purged");
 }
 
 /// A multimodal request parks in `Encoding` (submitted to the mm worker
@@ -861,7 +861,7 @@ fn mm_failure_rejects_parked_request() {
     assert!(consumer.drain(16).headers.is_empty(), "nothing queued");
 }
 
-/// On a non-multimodal model (`Mm::enabled == false`), image_data is silently
+/// On a non-multimodal model (`MmDispatch::enabled == false`), image_data is silently
 /// ignored and the request tokenizes as plain text — the Python
 /// TokenizerManager behavior when `mm_processor is None`.
 #[test]

rust/sglang-server/src/tokenizer_manager/to_scheduler_types.rs

@@ -3,19 +3,19 @@
 use crate::message::config::ServerArgs;
 use crate::message::request::MmRequest;
 
-/// The intake side of the MM path.
+/// Dispatches multimodal requests onto the MM worker channel.
 #[derive(Clone)]
-pub struct Mm {
+pub struct MmDispatch {
     /// Whether the model is multimodal. When false, mm fields are silently
     /// ignored, as the Python `TokenizerManager` does with `mm_processor is
     /// None`.
     pub enabled: bool,
     /// → MM worker pool (spawned via `Server.start_mm_workers`).
     pub tx: flume::Sender<MmRequest>,
-    /// Results sidecar. Purged here when a late result arrives for a request
+    /// Parked results. Purged here when a late result arrives for a request
     /// that is no longer parked; otherwise it would leak, since only the
     /// scheduler drain pops entries.
-    pub sidecar: crate::multi_modality::sidecar::Sidecar,
+    pub results: crate::multi_modality::result_store::MmResultStore,
 }
 
 /// Resolved once at boot from the scheduler's `server_args`.

rust/sglang-server/src/tokenizer_manager/wiring.rs

@@ -25,7 +25,7 @@ pub enum TmEvent {
     Tokenized(Request),
     /// An MM worker finished a request parked in `Encoding`: `input_ids` are the
     /// final placeholder-expanded prompt ids. The buffers ride the rid-keyed
-    /// sidecar (`Server.take_mm_result`), not this event.
+    /// result store (`Server.take_mm_result`), not this event.
     MmEncoded { rid: Rid, input_ids: Vec<i32> },
     /// An MM worker rejected a request parked in `Encoding` (bad media URL,
     /// unsupported modality, preprocess error, …).

rust/sglang-server/src/utils/runtime.rs

@@ -9,7 +9,7 @@
 //!   * To_scheduler   — 1 thread driving the FSM
 //!   * From_scheduler — 1 thread draining the scheduler → detok shards
 //!   * MM workers     — K unpinned OS threads, spawned late via
-//!     [`Runtime::spawn_mm_pool`] (multimodal models only)
+//!     [`Runtime::start_mm_workers`] (multimodal models only)
 //!
 //! Keeping CPU-bound tokenize/detokenize off the async executor avoids stalling
 //! axum's worker threads.
@@ -41,18 +41,11 @@ pub trait Runnable: Send + 'static {
 pub struct Runtime {
     pub to_scheduler_rx: ToSchedulerRx,
     pub from_scheduler_tx: FromSchedulerTx,
-    /// Requests parked in `Encoding`, drained by the MM worker pool
-    /// (`Server.start_mm_workers`). Stays empty for non-multimodal models —
-    /// request never routes to it.
-    pub to_mm_worker_rx: flume::Receiver<crate::message::request::MmRequest>,
-    /// Back-channel for the MM workers' `MmEncoded` / `MmFailed` into to_scheduler.
-    pub from_mm_worker_tx: flume::Sender<TmEvent>,
-    /// The loaded tokenizer, shared with the MM worker path (`None` under
-    /// `skip_tokenizer_init`).
-    pub tokenizer: Option<Arc<dyn tokenizer::TextTokenizer>>,
     /// MM results parked between a worker's `MmEncoded` and the scheduler drain
     /// (`Server.take_mm_result`).
-    pub mm_sidecar: crate::multi_modality::sidecar::Sidecar,
+    pub mm_results: crate::multi_modality::result_store::MmResultStore,
+    /// Wiring for the late-spawned MM pool ([`Runtime::start_mm_workers`]).
+    mm_wiring: crate::multi_modality::worker::MmWiring,
     /// Worker join handles, joined by `request_shutdown` / `Drop`.
     threads: Mutex<Vec<JoinHandle<()>>>,
     /// The single shutdown sender.
@@ -64,23 +57,34 @@ pub struct Runtime {
 const SHUTDOWN_JOIN_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(5);
 
 impl Runtime {
-    /// Spawn `workers` `mm-worker-{i}` threads into the shutdown join set —
-    /// late, once Python has built the mm spec (`Server::start_mm_workers`).
+    /// Build the family context from `spec` and spawn `workers`
+    /// `mm-worker-{i}` threads into the shutdown join set — late, once Python
+    /// has built the mm spec (`Server.start_mm_workers`).
     ///
     /// Deliberately unpinned: the threads inherit the launch thread's affinity,
     /// already narrowed by `RustServer.launch` to the server cores, so bursty
     /// MM preprocessing floats over that whole set (rather than owning cores
     /// that idle between bursts) and never preempts the scheduler's reserved
     /// cores.
-    pub fn spawn_mm_pool(&self, workers: usize, ctx: Arc<crate::multi_modality::worker::Context>) {
+    pub fn start_mm_workers(
+        &self,
+        spec: crate::message::config::MmSpec,
+        workers: usize,
+    ) -> Result<(), String> {
+        let ctx = Arc::new(crate::multi_modality::worker::MmContext::new(
+            spec,
+            self.mm_wiring.tokenizer.clone(),
+            self.mm_results.clone(),
+        )?);
         let mut threads = self.threads.lock().unwrap();
         spawn_pool("mm-worker", None, workers.max(1), &mut threads, |_| {
             crate::multi_modality::worker::MmWorker::new(
-                self.to_mm_worker_rx.clone(),
-                self.from_mm_worker_tx.clone(),
+                self.mm_wiring.mm_rx.clone(),
+                self.mm_wiring.tm_tx.clone(),
                 ctx.clone(),
             )
         });
+        Ok(())
     }
 
     /// Stop the runtime and join every worker thread (with a bounded wait).
@@ -165,7 +169,7 @@ pub fn start(cfg: RuntimeConfig) -> Result<Runtime, String> {
         .map(|t| Arc::new(tokenizer::DynamoTokenizer::new(t.clone())) as _);
 
     // Shared: MM workers park, the Python drain pops.
-    let mm_sidecar: crate::multi_modality::sidecar::Sidecar = Default::default();
+    let mm_results: crate::multi_modality::result_store::MmResultStore = Default::default();
 
     // --- Detokenizer shards (pinned, CPU bound) ---
     {
@@ -250,10 +254,10 @@ pub fn start(cfg: RuntimeConfig) -> Result<Runtime, String> {
             .and_then(|p| p.tm.get(1).or_else(|| p.tm.first()).copied())
             .map(|c| vec![c]);
         let limits = tokenizer_manager::to_scheduler::Limits::from(&*cfg.server_args);
-        let mm = tokenizer_manager::to_scheduler::Mm {
+        let mm = tokenizer_manager::to_scheduler::MmDispatch {
             enabled: cfg.server_args.model_is_multimodal(),
             tx: mm_worker_tx,
-            sidecar: mm_sidecar.clone(),
+            results: mm_results.clone(),
         };
         let mut parts = Some((tok_manager_rx, to_scheduler_tx)); // moved into the single worker
         let shutdown_rx = shutdown_rx.clone();
@@ -318,10 +322,12 @@ pub fn start(cfg: RuntimeConfig) -> Result<Runtime, String> {
     Ok(Runtime {
         to_scheduler_rx,
         from_scheduler_tx,
-        to_mm_worker_rx: mm_worker_rx,
-        from_mm_worker_tx: tok_manager_tx,
-        tokenizer: text_tokenizer,
-        mm_sidecar,
+        mm_results,
+        mm_wiring: crate::multi_modality::worker::MmWiring {
+            mm_rx: mm_worker_rx,
+            tm_tx: tok_manager_tx,
+            tokenizer: text_tokenizer,
+        },
         threads: Mutex::new(threads),
         shutdown_tx: Mutex::new(Some(shutdown_tx)),
     })

test/registered/unit/multimodal/rust/qwen/test_e2e_parity.py

@@ -1,7 +1,7 @@
 """End-to-end parity at the scheduler-input boundary.
 
 `test_preprocess.py` pins the `preprocess` binding; this drives the whole native
-path — the `process_mm` driver, then `RustMmProcessor.build_output` — and
+path — the `process_mm` driver, then `RustMmProcessor.wrap_encoded` — and
 compares every field the scheduler reads against the Python `mm_processor`.
 Bitwise, for both HF backends: the Rust resize clones PIL's fixed-point bicubic
 and ATen's uint8 antialias kernel, so whichever one a server is configured with
@@ -82,9 +82,9 @@ class TestQwenE2eParity(CustomTestCase):
         ids, features, grids, hashes, offsets, mrope, delta = DRIVER(
             PROMPT_PER_IMAGE * len(sources), sources, spec.rust_json()
         )
-        # The shape of Rust's MmEncodeResult, inline transport (test_build_output
-        # pins the shm shape).
-        handoff = SimpleNamespace(
+        # The shape of Rust's MmEncodedResult, inline transport
+        # (test_wrap_encoded pins the shm shape).
+        encoded = SimpleNamespace(
             features=features,
             shm_names=None,
             grids=grids,
@@ -93,7 +93,7 @@ class TestQwenE2eParity(CustomTestCase):
             mrope=mrope,
             mrope_delta=delta,
         )
-        return snapshot(ids, RustMmProcessor.build_output(spec, handoff))
+        return snapshot(ids, RustMmProcessor.wrap_encoded(spec, encoded))
 
     def run_python(self, sources):
         """The reference path: the Python `mm_processor` the scheduler would use."""

test/registered/unit/multimodal/rust/qwen/test_rust_mm_processor.py

@@ -49,6 +49,8 @@ class TestQwenRustMmHashes(CustomTestCase):
     def setUp(self):
         from sglang.srt.managers.multimodal_processor import import_processors
 
+        # The hash helper builds RustMmProcessor via __new__ (no __init__),
+        # so processors must be registered here for resolve_spec's lookup.
         import_processors("sglang.srt.multimodal.processors")
         self.processor = make_processor(self, PROCESSOR_CONFIGS["qwen2_5_vl"])
 

test/registered/unit/multimodal/rust/shared/test_wrap_encoded.py

@@ -1,4 +1,4 @@
-"""``RustMmProcessor.build_output``: the drain-time
+"""``RustMmProcessor.wrap_encoded``: the drain-time
 wrapping contracts — tensors are zero-copy views over the Rust-owned buffers, and
 pad values come from worker-precomputed hashes, since the scheduler loop must
 never hash features. Synthetic buffers, so this needs no Rust extension."""
@@ -23,7 +23,7 @@ from sglang.srt.rust_server.multimodal import (  # noqa: E402
 register_cpu_ci(est_time=3, suite="base-a-test-cpu")
 
 
-class TestBuildRustMmOutput(CustomTestCase):
+class TestWrapEncoded(CustomTestCase):
     def setUp(self):
         # feature_dim == 3 * temporal_patch_size * patch_size**2 == 6.
         self.spec = RustMmSpec(
@@ -53,9 +53,9 @@ class TestBuildRustMmOutput(CustomTestCase):
 
     def build(self):
         features = np.arange(30, dtype=np.float32)
-        output = RustMmProcessor.build_output(
+        output = RustMmProcessor.wrap_encoded(
             self.spec,
-            SimpleNamespace(  # the shape of Rust's MmEncodeResult
+            SimpleNamespace(  # the shape of Rust's MmEncodedResult
                 grids=self.GRIDS,
                 hashes=self.HASHES,
                 offsets=self.OFFSETS,
@@ -102,7 +102,7 @@ class TestBuildRustMmOutput(CustomTestCase):
         )
 
 
-class TestBuildRustMmOutputShm(TestBuildRustMmOutput):
+class TestWrapEncodedShm(TestWrapEncoded):
     """The shm entry shape (TP>1): features arrive as named POSIX segments, and
     each item becomes a ``ShmPointerMMData`` stub whose ``materialize()`` yields
     that item's slice — and unlinks, taking the cleanup duty exactly once."""