Files
agentic-pd-hybrid/third_party/sglang/sgl-model-gateway/src/policies/registry.rs

513 lines
20 KiB
Rust

use std::sync::{Arc, OnceLock, RwLock};
use dashmap::DashMap;
use serde_json;
use smg_mesh::OptionalMeshSyncManager;
use tracing::{debug, info, warn};
/// Policy Registry for managing model-to-policy mappings
///
/// This registry manages the dynamic assignment of load balancing policies to models.
/// When the first worker of a new model is added, it determines the policy for that model.
/// All subsequent workers of the same model use the established policy.
/// When the last worker of a model is removed, the policy mapping is cleaned up.
use super::{BucketPolicy, CacheAwarePolicy, LoadBalancingPolicy, PolicyFactory};
use crate::{config::types::PolicyConfig, core::Worker};
/// Registry for managing model-to-policy mappings
#[derive(Clone)]
pub struct PolicyRegistry {
/// Model ID -> Policy instance mapping (lock-free reads via DashMap)
model_policies: Arc<DashMap<String, Arc<dyn LoadBalancingPolicy>>>,
/// Model ID -> Worker count for cleanup tracking (lock-free reads via DashMap)
model_worker_counts: Arc<DashMap<String, usize>>,
/// Default policy instance (cached, immutable after creation)
default_policy: Arc<dyn LoadBalancingPolicy>,
/// Prefill policy for PD mode (set once at startup, lock-free reads via OnceLock)
prefill_policy: Arc<OnceLock<Arc<dyn LoadBalancingPolicy>>>,
/// Decode policy for PD mode (set once at startup, lock-free reads via OnceLock)
decode_policy: Arc<OnceLock<Arc<dyn LoadBalancingPolicy>>>,
/// Optional mesh sync manager for state synchronization
/// When None, the registry works independently without mesh synchronization
/// Uses RwLock for thread-safe access when setting mesh_sync after initialization
mesh_sync: Arc<RwLock<OptionalMeshSyncManager>>,
}
impl PolicyRegistry {
/// Create a new PolicyRegistry with a default policy
pub fn new(default_policy_config: PolicyConfig) -> Self {
let default_policy = Self::create_policy_from_config(&default_policy_config);
Self {
model_policies: Arc::new(DashMap::new()),
model_worker_counts: Arc::new(DashMap::new()),
default_policy,
prefill_policy: Arc::new(OnceLock::new()),
decode_policy: Arc::new(OnceLock::new()),
mesh_sync: Arc::new(RwLock::new(None)),
}
}
/// Set mesh sync manager (thread-safe, can be called after initialization)
pub fn set_mesh_sync(&self, mesh_sync: OptionalMeshSyncManager) {
*self.mesh_sync.write().unwrap() = mesh_sync;
}
/// Called when a worker is added
/// Returns the policy that should be used for this worker's model
pub fn on_worker_added(
&self,
model_id: &str,
policy_hint: Option<&str>,
) -> Arc<dyn LoadBalancingPolicy> {
// Increment worker count using DashMap entry API
let count = self
.model_worker_counts
.entry(model_id.to_string())
.and_modify(|c| *c += 1)
.or_insert(1);
debug!("Worker added for model {}, count: {}", model_id, *count);
drop(count); // Release the entry lock
// Check if model already has a policy (lock-free read via DashMap)
if let Some(existing_policy) = self.model_policies.get(model_id) {
debug!(
"Model {} already has policy: {}",
model_id,
existing_policy.name()
);
return Arc::clone(&existing_policy);
}
// New model - determine policy
let policy = self.determine_policy_for_model(model_id, policy_hint);
info!(
"Assigning policy {} to new model {}",
policy.name(),
model_id
);
// Store policy for this model (DashMap handles concurrent inserts)
self.model_policies
.insert(model_id.to_string(), Arc::clone(&policy));
// Sync to mesh if enabled (no-op if mesh is not enabled)
if let Some(ref mesh_sync) = *self.mesh_sync.read().unwrap() {
// Serialize policy config (simplified - just store policy name for now)
let config = serde_json::to_vec(&policy.name()).unwrap_or_default();
mesh_sync.sync_policy_state(model_id.to_string(), policy.name().to_string(), config);
}
policy
}
/// Called when a worker is removed
pub fn on_worker_removed(&self, model_id: &str) {
// Decrement worker count and check if cleanup needed
let should_cleanup = if let Some(mut count_ref) = self.model_worker_counts.get_mut(model_id)
{
*count_ref = count_ref.saturating_sub(1);
debug!(
"Worker removed for model {}, count: {}",
model_id, *count_ref
);
if *count_ref == 0 {
drop(count_ref); // Release before remove
self.model_worker_counts.remove(model_id);
true
} else {
false
}
} else {
warn!(
"Attempted to remove worker for model {} with no registered workers",
model_id
);
false
};
// Clean up policy if this was the last worker
if should_cleanup {
if let Some((_, policy)) = self.model_policies.remove(model_id) {
info!(
"Removed policy {} for model {} (last worker removed)",
policy.name(),
model_id
);
}
// Sync removal to mesh if enabled (no-op if mesh is not enabled)
if let Some(ref mesh_sync) = *self.mesh_sync.read().unwrap() {
mesh_sync.remove_policy_state(model_id);
}
}
}
/// Get the policy for a model (lock-free via DashMap)
pub fn get_policy(&self, model_id: &str) -> Option<Arc<dyn LoadBalancingPolicy>> {
self.model_policies.get(model_id).map(|r| Arc::clone(&r))
}
/// Get the default policy
pub fn get_default_policy(&self) -> Arc<dyn LoadBalancingPolicy> {
Arc::clone(&self.default_policy)
}
/// Get policy for a model, or default if not found
pub fn get_policy_or_default(&self, model_id: &str) -> Arc<dyn LoadBalancingPolicy> {
self.get_policy(model_id)
.unwrap_or_else(|| self.get_default_policy())
}
/// Determine policy for a new model
fn determine_policy_for_model(
&self,
model_id: &str,
policy_hint: Option<&str>,
) -> Arc<dyn LoadBalancingPolicy> {
// 1. Check policy hint from worker
if let Some(policy_type) = policy_hint {
debug!("Using policy hint '{}' for model {}", policy_type, model_id);
return self.create_policy_from_type(policy_type);
}
// 2. Use default policy
debug!("Using default policy for model {}", model_id);
Arc::clone(&self.default_policy)
}
/// Create a policy from a type string (delegates to PolicyFactory)
fn create_policy_from_type(&self, policy_type: &str) -> Arc<dyn LoadBalancingPolicy> {
if policy_type == "cache_aware" {
let mut cache_aware = CacheAwarePolicy::new();
let mesh_sync = &*self.mesh_sync.read().unwrap();
cache_aware.set_mesh_sync(mesh_sync.clone());
Arc::new(cache_aware)
} else {
PolicyFactory::create_by_name(policy_type).unwrap_or_else(|| {
warn!("Unknown policy type '{}', using default", policy_type);
Arc::clone(&self.default_policy)
})
}
}
/// Create a policy from a PolicyConfig (delegates to PolicyFactory)
fn create_policy_from_config(config: &PolicyConfig) -> Arc<dyn LoadBalancingPolicy> {
PolicyFactory::create_from_config(config)
}
/// Get current model->policy mappings (for debugging/monitoring)
pub fn get_all_mappings(&self) -> std::collections::HashMap<String, String> {
self.model_policies
.iter()
.map(|entry| (entry.key().clone(), entry.value().name().to_string()))
.collect()
}
/// Get worker counts per model
pub fn get_worker_counts(&self) -> std::collections::HashMap<String, usize> {
self.model_worker_counts
.iter()
.map(|entry| (entry.key().clone(), *entry.value()))
.collect()
}
/// Clear all policies (useful for testing)
pub fn clear(&self) {
self.model_policies.clear();
self.model_worker_counts.clear();
}
/// Set the prefill policy for PD mode (lock-free, set once at startup)
pub fn set_prefill_policy(&self, policy: Arc<dyn LoadBalancingPolicy>) {
// OnceLock::set returns Err if already set, which we ignore since
// the policy should only be set once at startup
let _ = self.prefill_policy.set(policy);
}
/// Set the decode policy for PD mode (lock-free, set once at startup)
pub fn set_decode_policy(&self, policy: Arc<dyn LoadBalancingPolicy>) {
// OnceLock::set returns Err if already set, which we ignore since
// the policy should only be set once at startup
let _ = self.decode_policy.set(policy);
}
/// Get the prefill policy for PD mode, or default if not set (lock-free)
pub fn get_prefill_policy(&self) -> Arc<dyn LoadBalancingPolicy> {
self.prefill_policy
.get()
.map(Arc::clone)
.unwrap_or_else(|| self.get_default_policy())
}
/// Get the decode policy for PD mode, or default if not set (lock-free)
pub fn get_decode_policy(&self) -> Arc<dyn LoadBalancingPolicy> {
self.decode_policy
.get()
.map(Arc::clone)
.unwrap_or_else(|| self.get_default_policy())
}
/// Get all PowerOfTwo policies that need load updates (lock-free)
pub fn get_all_power_of_two_policies(&self) -> Vec<Arc<dyn LoadBalancingPolicy>> {
let mut power_of_two_policies = Vec::new();
if self.default_policy.name() == "power_of_two" {
power_of_two_policies.push(Arc::clone(&self.default_policy));
}
// Get prefill and decode policies (lock-free via OnceLock::get)
let prefill_policy_opt = self.prefill_policy.get();
let decode_policy_opt = self.decode_policy.get();
if let Some(policy) = prefill_policy_opt {
if policy.name() == "power_of_two" && !Arc::ptr_eq(policy, &self.default_policy) {
power_of_two_policies.push(Arc::clone(policy));
}
}
if let Some(policy) = decode_policy_opt {
if policy.name() == "power_of_two"
&& !Arc::ptr_eq(policy, &self.default_policy)
&& !prefill_policy_opt.is_some_and(|p| Arc::ptr_eq(p, policy))
{
power_of_two_policies.push(Arc::clone(policy));
}
}
for entry in self.model_policies.iter() {
let policy = entry.value();
if policy.name() == "power_of_two" {
let already_added = power_of_two_policies.iter().any(|p| Arc::ptr_eq(p, policy));
if !already_added {
power_of_two_policies.push(Arc::clone(policy));
}
}
}
power_of_two_policies
}
/// Initialize cache-aware policy with workers if applicable
/// This should be called after workers are registered for a model
pub fn init_cache_aware_policy(&self, model_id: &str, workers: &[Arc<dyn Worker>]) {
// Get the policy for this model
if let Some(policy) = self.get_policy(model_id) {
if policy.name() == "cache_aware" {
if let Some(cache_aware) = policy.as_any().downcast_ref::<CacheAwarePolicy>() {
debug!(
"Initializing cache-aware policy with {} workers for model {}",
workers.len(),
model_id
);
cache_aware.init_workers(workers);
}
}
}
}
/// Remove a worker from cache-aware policy if applicable
/// This should be called when a worker is being removed
pub fn remove_worker_from_cache_aware(&self, model_id: &str, worker_url: &str) {
// Get the policy for this model
if let Some(policy) = self.get_policy(model_id) {
if policy.name() == "cache_aware" {
if let Some(cache_aware) = policy.as_any().downcast_ref::<CacheAwarePolicy>() {
cache_aware.remove_worker_by_url(worker_url);
debug!(
"Removed worker {} from cache-aware policy for model {}",
worker_url, model_id
);
}
}
}
}
/// Initialize cache-aware policies for PD mode (prefill and decode) - lock-free
pub fn init_pd_cache_aware_policies(
&self,
prefill_workers: &[Arc<dyn Worker>],
decode_workers: &[Arc<dyn Worker>],
) {
// Initialize prefill policy if it's cache-aware (lock-free via OnceLock::get)
if let Some(prefill_policy) = self.prefill_policy.get() {
if prefill_policy.name() == "cache_aware" {
if let Some(cache_aware) =
prefill_policy.as_any().downcast_ref::<CacheAwarePolicy>()
{
if !prefill_workers.is_empty() {
debug!(
"Initializing prefill cache-aware policy with {} workers",
prefill_workers.len()
);
cache_aware.init_workers(prefill_workers);
}
}
}
}
// Initialize decode policy if it's cache-aware (lock-free via OnceLock::get)
if let Some(decode_policy) = self.decode_policy.get() {
if decode_policy.name() == "cache_aware" {
if let Some(cache_aware) = decode_policy.as_any().downcast_ref::<CacheAwarePolicy>()
{
if !decode_workers.is_empty() {
debug!(
"Initializing decode cache-aware policy with {} workers",
decode_workers.len()
);
cache_aware.init_workers(decode_workers);
}
}
}
}
}
/// Initialize bucket policies for PD mode - lock-free
pub fn init_pd_bucket_policies(&self, prefill_workers: &[Arc<dyn Worker>]) {
// Initialize prefill policy if it's bucket (lock-free via OnceLock::get)
if let Some(prefill_policy) = self.prefill_policy.get() {
if prefill_policy.name() == "bucket" {
if let Some(bucket) = prefill_policy.as_any().downcast_ref::<BucketPolicy>() {
if !prefill_workers.is_empty() {
debug!(
"Initializing prefill bucket policy with {} workers",
prefill_workers.len()
);
bucket.init_prefill_worker_urls(prefill_workers);
}
}
}
}
}
/// Apply remote tree operation to cache-aware policy for a model
/// This is called when receiving tree state updates from mesh
pub fn apply_remote_tree_operation(
&self,
model_id: &str,
operation: &smg_mesh::tree_ops::TreeOperation,
) {
// Try to find the policy for this model
if let Some(policy) = self.get_policy(model_id) {
if policy.name() == "cache_aware" {
if let Some(cache_aware) = policy.as_any().downcast_ref::<CacheAwarePolicy>() {
cache_aware.apply_remote_tree_operation(model_id, operation);
}
}
}
// Also check default policy if it's cache-aware
if self.default_policy.name() == "cache_aware" {
if let Some(cache_aware) = self
.default_policy
.as_any()
.downcast_ref::<CacheAwarePolicy>()
{
cache_aware.apply_remote_tree_operation(model_id, operation);
}
}
// Check prefill and decode policies for PD mode
if let Some(prefill_policy) = self.prefill_policy.get() {
if prefill_policy.name() == "cache_aware" {
if let Some(cache_aware) =
prefill_policy.as_any().downcast_ref::<CacheAwarePolicy>()
{
cache_aware.apply_remote_tree_operation(model_id, operation);
}
}
}
if let Some(decode_policy) = self.decode_policy.get() {
if decode_policy.name() == "cache_aware" {
if let Some(cache_aware) = decode_policy.as_any().downcast_ref::<CacheAwarePolicy>()
{
cache_aware.apply_remote_tree_operation(model_id, operation);
}
}
}
}
}
impl std::fmt::Debug for PolicyRegistry {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("PolicyRegistry")
.field("model_policies", &self.model_policies)
.field("model_worker_counts", &self.model_worker_counts)
.field("default_policy", &self.default_policy.name())
.finish()
}
}
#[cfg(test)]
mod tests {
use super::*;
#[tokio::test]
async fn test_policy_registry_basic() {
let registry = PolicyRegistry::new(PolicyConfig::RoundRobin);
// First worker of a model sets the policy
let policy1 = registry.on_worker_added("llama-3", Some("cache_aware"));
assert_eq!(policy1.name(), "cache_aware");
// Second worker of same model uses existing policy
let policy2 = registry.on_worker_added("llama-3", Some("round_robin"));
assert_eq!(policy2.name(), "cache_aware"); // Ignores hint, uses existing
// Different model can have different policy
let policy3 = registry.on_worker_added("gpt-4", Some("random"));
assert_eq!(policy3.name(), "random");
// Check mappings
let mappings = registry.get_all_mappings();
assert_eq!(mappings.get("llama-3").unwrap(), "cache_aware");
assert_eq!(mappings.get("gpt-4").unwrap(), "random");
// Check worker counts
let counts = registry.get_worker_counts();
assert_eq!(*counts.get("llama-3").unwrap(), 2);
assert_eq!(*counts.get("gpt-4").unwrap(), 1);
}
#[tokio::test]
async fn test_policy_registry_cleanup() {
let registry = PolicyRegistry::new(PolicyConfig::RoundRobin);
// Add workers
registry.on_worker_added("llama-3", Some("cache_aware"));
registry.on_worker_added("llama-3", None);
assert_eq!(registry.get_worker_counts().get("llama-3"), Some(&2));
// Remove one worker - policy should remain
registry.on_worker_removed("llama-3");
assert!(registry.get_policy("llama-3").is_some());
assert_eq!(registry.get_worker_counts().get("llama-3"), Some(&1));
// Remove last worker - policy should be cleaned up
registry.on_worker_removed("llama-3");
assert!(registry.get_policy("llama-3").is_none());
assert_eq!(registry.get_worker_counts().get("llama-3"), None);
}
#[tokio::test]
async fn test_default_policy() {
let registry = PolicyRegistry::new(PolicyConfig::RoundRobin);
// No hint, no template - uses default
let policy = registry.on_worker_added("unknown-model", None);
assert_eq!(policy.name(), "round_robin");
// Get default directly
let default = registry.get_default_policy();
assert_eq!(default.name(), "round_robin");
}
}