Gahow Wang
3594f7dce0
LMetric was incorrectly sharing session-sticky logic with Linear policy. Fixed to pure per-request routing: score = P_tokens × BS where P = pending_prefill + (input - cache_hit), BS = num_requests. Experiment result (200 req, fresh restart): Linear vs corrected LMetric show <2% difference on all metrics — LMetric's cache-hit estimation provides implicit soft affinity that preserves locality without explicit session stickiness. Also fix bench.sh missing cd (replayer module not found from non-project cwd) and rewrite run_lmetric_ab.sh as thin wrapper around bench.sh to eliminate duplicated launch/cleanup logic that broke under set -euo. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
642 lines
25 KiB
Python
642 lines
25 KiB
Python
"""Unified cache-aware + token-level load-balanced global scheduler.
|
||
|
||
Supports two modes:
|
||
--combined URL [URL ...]: PD co-located instances (normal vLLM, no KV transfer)
|
||
--prefill URL BP --decode URL: PD disaggregated instances (Mooncake KV transfer)
|
||
|
||
Routing policies (--policy):
|
||
linear (default): score = ongoing_tokens - ALPHA * cache_hit_tokens
|
||
lmetric: score = P_tokens * BS (LMetric, OSDI'26)
|
||
P_tokens = pending_prefill_tokens + new_uncached_tokens
|
||
BS = num_requests (waiting + running)
|
||
Session affinity: multi-turn sessions stick to same instance (all policies).
|
||
"""
|
||
|
||
import argparse
|
||
import asyncio
|
||
import os
|
||
import time as _time
|
||
import urllib.parse
|
||
import uuid
|
||
from contextlib import asynccontextmanager
|
||
|
||
import httpx
|
||
import uvicorn
|
||
from fastapi import FastAPI, HTTPException, Request
|
||
from fastapi.responses import StreamingResponse
|
||
|
||
BLOCK_SIZE = 512
|
||
CACHE_HIT_ALPHA = 1.0
|
||
HEAVY_THRESHOLD = 20000 # default; overridden by --heavy-threshold
|
||
OVERLOAD_FACTOR = 2.0 # default; overridden by --overload-factor
|
||
|
||
|
||
class InstanceState:
|
||
def __init__(self, url: str, bootstrap_port: int | None = None):
|
||
self.url = url
|
||
self.bootstrap_port = bootstrap_port
|
||
self.client = httpx.AsyncClient(
|
||
timeout=None, base_url=url,
|
||
limits=httpx.Limits(max_connections=None, max_keepalive_connections=None),
|
||
)
|
||
self.ongoing_tokens = 0
|
||
self.ongoing_decode_tokens = 0 # subset: tokens in decode phase
|
||
self.pending_prefill_tokens = 0 # tokens for requests still in prefill
|
||
self.num_requests = 0 # total in-flight requests (waiting + running)
|
||
self.active_p_offloads = 0 # number of HEAVY prefills this instance is doing for others
|
||
self.engine_id: dict[int, str] = {}
|
||
self.dp_size = 1
|
||
self.cached_blocks: set[int] = set()
|
||
|
||
def estimate_cache_hit(self, token_ids: list[int] | None) -> int:
|
||
if not token_ids or len(token_ids) < BLOCK_SIZE:
|
||
return 0
|
||
hit = 0
|
||
for i in range(0, len(token_ids) - BLOCK_SIZE + 1, BLOCK_SIZE):
|
||
bh = hash(tuple(token_ids[i:i + BLOCK_SIZE]))
|
||
if bh in self.cached_blocks:
|
||
hit += BLOCK_SIZE
|
||
else:
|
||
break
|
||
return hit
|
||
|
||
def record_prefix(self, token_ids: list[int] | None):
|
||
if not token_ids:
|
||
return
|
||
for i in range(0, len(token_ids) - BLOCK_SIZE + 1, BLOCK_SIZE):
|
||
self.cached_blocks.add(hash(tuple(token_ids[i:i + BLOCK_SIZE])))
|
||
if len(self.cached_blocks) > 200000:
|
||
self.cached_blocks = set(list(self.cached_blocks)[-100000:])
|
||
|
||
|
||
# Cumulative token load per instance (for balanced session placement)
|
||
_inst_cumulative_tokens: list[int] = []
|
||
|
||
|
||
def _p_offload_penalty(inst: InstanceState) -> int:
|
||
"""Penalty for instances currently doing P-role offloaded prefills.
|
||
|
||
When an instance is busy with offloaded HEAVY prefills for other
|
||
instances, we want to steer WARM/MEDIUM requests away from it so
|
||
its GPU is dedicated to prefill (soft PD separation).
|
||
"""
|
||
if inst.active_p_offloads <= 0:
|
||
return 0
|
||
return inst.active_p_offloads * HEAVY_THRESHOLD
|
||
|
||
|
||
def pick_instance(instances: list[InstanceState], token_ids: list[int] | None,
|
||
session_id: str | None, input_length: int,
|
||
affinity: dict[str, int]) -> tuple[InstanceState, int]:
|
||
"""Session-sticky with load-aware override.
|
||
|
||
Turn 2+: use session affinity UNLESS pinned instance is overloaded
|
||
or busy with P-role offloads, in which case pick least-loaded.
|
||
Turn 1: pick instance with best score (load + cache combined).
|
||
Instances doing P-role offloads get a large penalty to steer
|
||
WARM/MEDIUM traffic away.
|
||
"""
|
||
global _inst_cumulative_tokens
|
||
if not _inst_cumulative_tokens:
|
||
_inst_cumulative_tokens = [0] * len(instances)
|
||
|
||
avg_load = max(sum(i.ongoing_tokens for i in instances) / len(instances), 1.0)
|
||
|
||
if session_id and session_id in affinity:
|
||
idx = affinity[session_id]
|
||
if idx < len(instances):
|
||
inst = instances[idx]
|
||
if (inst.ongoing_tokens <= avg_load * OVERLOAD_FACTOR
|
||
and inst.active_p_offloads == 0):
|
||
return inst, idx
|
||
|
||
best_idx, best_score = 0, float("inf")
|
||
for i, inst in enumerate(instances):
|
||
cache_hit = inst.estimate_cache_hit(token_ids)
|
||
score = (inst.ongoing_tokens + _p_offload_penalty(inst)
|
||
- CACHE_HIT_ALPHA * cache_hit)
|
||
if score < best_score:
|
||
best_score = score
|
||
best_idx = i
|
||
|
||
_inst_cumulative_tokens[best_idx] += input_length
|
||
if session_id:
|
||
affinity[session_id] = best_idx
|
||
return instances[best_idx], best_idx
|
||
|
||
|
||
def pick_instance_lmetric(instances: list[InstanceState], token_ids: list[int] | None,
|
||
session_id: str | None, input_length: int,
|
||
affinity: dict[str, int]) -> tuple[InstanceState, int]:
|
||
"""LMetric routing: score = P_tokens × BS (OSDI'26).
|
||
|
||
Pure per-request load-based routing, no session affinity.
|
||
P = pending_prefill_tokens + (input_length - cache_hit)
|
||
BS = num_requests (current batch size)
|
||
"""
|
||
best_idx, best_score = 0, float("inf")
|
||
for i, inst in enumerate(instances):
|
||
cache_hit = inst.estimate_cache_hit(token_ids)
|
||
new_prefill = max(0, input_length - cache_hit)
|
||
p_tokens = inst.pending_prefill_tokens + new_prefill
|
||
bs = inst.num_requests
|
||
score = p_tokens * bs
|
||
if score < best_score:
|
||
best_score = score
|
||
best_idx = i
|
||
|
||
return instances[best_idx], best_idx
|
||
|
||
|
||
global_args = None
|
||
combined_instances: list[InstanceState] = []
|
||
prefill_instances: list[InstanceState] = []
|
||
decode_instances: list[InstanceState] = []
|
||
session_affinity: dict[str, int] = {}
|
||
is_pd_sep = False
|
||
_breakdown_log: list[dict] = []
|
||
|
||
|
||
async def init_prefill_bootstrap(instances: list[InstanceState], ready: asyncio.Event):
|
||
for inst in instances:
|
||
if inst.bootstrap_port is None:
|
||
continue
|
||
while True:
|
||
try:
|
||
await inst.client.get("/health")
|
||
except Exception:
|
||
await asyncio.sleep(1)
|
||
continue
|
||
parsed = urllib.parse.urlparse(str(inst.client.base_url))
|
||
url = f"http://{parsed.hostname}:{inst.bootstrap_port}/query"
|
||
resp = await inst.client.get(url)
|
||
resp.raise_for_status()
|
||
data = resp.json()
|
||
for dp_rank, dp_entry in data.items():
|
||
inst.engine_id[int(dp_rank)] = dp_entry["engine_id"]
|
||
inst.dp_size = len(data)
|
||
print(f"Inited {inst.url} engine_ids={inst.engine_id}")
|
||
break
|
||
ready.set()
|
||
|
||
|
||
@asynccontextmanager
|
||
async def lifespan(app: FastAPI):
|
||
global is_pd_sep
|
||
app.state.ready = asyncio.Event()
|
||
|
||
if global_args.combined:
|
||
is_pd_sep = False
|
||
bp_list = [int(p) for p in global_args.bootstrap_ports.split(",") if p.strip()] if global_args.bootstrap_ports else []
|
||
for i, url in enumerate(global_args.combined):
|
||
bp = bp_list[i] if i < len(bp_list) else None
|
||
combined_instances.append(InstanceState(url, bp))
|
||
|
||
# Bootstrap combined instances for offload (need engine_ids for KV transfer)
|
||
if global_args.offload and bp_list:
|
||
await init_prefill_bootstrap(combined_instances, app.state.ready)
|
||
else:
|
||
app.state.ready.set()
|
||
|
||
policy = getattr(global_args, 'policy', 'linear')
|
||
print(f"Combined mode: {len(combined_instances)} instances, policy={policy}, offload={'ON' if global_args.offload else 'OFF'}")
|
||
else:
|
||
is_pd_sep = True
|
||
for url, bp in global_args.prefill:
|
||
prefill_instances.append(InstanceState(url, bp))
|
||
for url in global_args.decode:
|
||
decode_instances.append(InstanceState(url))
|
||
await init_prefill_bootstrap(prefill_instances, app.state.ready)
|
||
print(f"PD-Sep mode: {len(prefill_instances)}P + {len(decode_instances)}D")
|
||
|
||
yield
|
||
for inst in combined_instances + prefill_instances + decode_instances:
|
||
await inst.client.aclose()
|
||
|
||
|
||
app = FastAPI(lifespan=lifespan)
|
||
|
||
|
||
@app.post("/v1/completions")
|
||
async def handle_completions(request: Request):
|
||
return await _handle(request, "/v1/completions")
|
||
|
||
|
||
@app.post("/v1/chat/completions")
|
||
async def handle_chat(request: Request):
|
||
return await _handle(request, "/v1/chat/completions")
|
||
|
||
|
||
async def _handle(request: Request, api: str):
|
||
if not app.state.ready.is_set():
|
||
raise HTTPException(status_code=503, detail="Service Unavailable")
|
||
|
||
req_data = await request.json()
|
||
request_id = str(uuid.uuid4())
|
||
prompt = req_data.get("prompt")
|
||
token_ids = prompt if isinstance(prompt, list) else None
|
||
input_length = len(token_ids) if token_ids else 0
|
||
session_id = request.headers.get("X-Session-Id")
|
||
|
||
headers = {"X-Request-Id": request_id}
|
||
api_key = os.environ.get("OPENAI_API_KEY")
|
||
if api_key:
|
||
headers["Authorization"] = f"Bearer {api_key}"
|
||
|
||
if is_pd_sep:
|
||
return await _handle_pd_sep(api, req_data, request_id, token_ids,
|
||
input_length, session_id, headers)
|
||
else:
|
||
return await _handle_combined(api, req_data, token_ids,
|
||
input_length, session_id, headers)
|
||
|
||
|
||
async def _handle_combined(api, req_data, token_ids, input_length, session_id, headers):
|
||
"""Combined mode with V2 P2P offload.
|
||
|
||
WARM/MEDIUM: route to best instance, co-located P+D (no KV transfer).
|
||
HEAVY: C_s (session-sticky, has cache) does FAST prefill,
|
||
D (least-loaded C, D != C_s) pulls KV via Mooncake and decodes.
|
||
Offload only when D is meaningfully less loaded than C_s.
|
||
"""
|
||
policy = getattr(global_args, 'policy', 'linear') if global_args else 'linear'
|
||
picker = pick_instance_lmetric if policy == 'lmetric' else pick_instance
|
||
best_inst, best_idx = picker(combined_instances, token_ids, session_id,
|
||
input_length, session_affinity)
|
||
cache_hit = best_inst.estimate_cache_hit(token_ids)
|
||
estimated_new = max(0, input_length - cache_hit)
|
||
|
||
breakdown = {
|
||
"request_id": headers.get("X-Request-Id", ""),
|
||
"input_length": input_length,
|
||
"estimated_new_tokens": estimated_new,
|
||
"cache_hit": cache_hit,
|
||
"t_proxy_recv": _time.monotonic(),
|
||
}
|
||
|
||
# H4 cache-aware offload gate: only offload when C_s has significant cache
|
||
# Cold turn-1 HEAVY: stay co-located (no RDMA overhead)
|
||
# Cached turn-2+ HEAVY: offload to flexible D (C_s fast prefill + D decode)
|
||
offload_enabled = getattr(global_args, 'offload', False) and len(combined_instances) >= 2
|
||
use_offload = False
|
||
offload_reason = "offload_disabled"
|
||
|
||
if estimated_new >= HEAVY_THRESHOLD and offload_enabled:
|
||
cache_ratio = cache_hit / max(input_length, 1)
|
||
d_candidate = min((c for c in combined_instances if c is not best_inst),
|
||
key=lambda c: c.ongoing_tokens)
|
||
breakdown["cache_ratio"] = cache_ratio
|
||
|
||
if cache_ratio >= 0.3: # at least 30% cache hit to justify RDMA offload
|
||
use_offload = True
|
||
offload_reason = "cached_offload_%.0f%%" % (cache_ratio * 100)
|
||
else:
|
||
offload_reason = "cold_colocated_%.0f%%" % (cache_ratio * 100)
|
||
|
||
if use_offload:
|
||
# C_s does fast cached prefill, D does decode
|
||
p_inst = best_inst # session-sticky, has prefix cache
|
||
d_inst = d_candidate
|
||
d_idx = combined_instances.index(d_inst)
|
||
|
||
# Accounting: C_s only prefills estimated_new tokens (cached prefix is free)
|
||
p_inst.ongoing_tokens += input_length
|
||
p_inst.pending_prefill_tokens += estimated_new
|
||
p_inst.num_requests += 1
|
||
p_inst.active_p_offloads += 1
|
||
|
||
breakdown["route_class"] = "HEAVY_OFFLOAD"
|
||
breakdown["offload_reason"] = offload_reason
|
||
breakdown["p_inst"] = p_inst.url
|
||
breakdown["d_inst"] = d_inst.url
|
||
breakdown["p_load"] = p_inst.ongoing_tokens
|
||
breakdown["d_load"] = d_inst.ongoing_tokens
|
||
|
||
# Update session affinity to D (D will have KV after this request)
|
||
if session_id:
|
||
session_affinity[session_id] = d_idx
|
||
|
||
return await _handle_heavy_offload(api, req_data, headers, token_ids,
|
||
input_length, p_inst, d_inst, breakdown)
|
||
else:
|
||
if estimated_new >= HEAVY_THRESHOLD:
|
||
breakdown["route_class"] = "HEAVY_COLO"
|
||
breakdown["offload_reason"] = offload_reason
|
||
elif estimated_new < 5000:
|
||
breakdown["route_class"] = "WARM"
|
||
else:
|
||
breakdown["route_class"] = "MEDIUM"
|
||
|
||
inst = best_inst
|
||
breakdown["routed_to"] = inst.url
|
||
breakdown["policy"] = policy
|
||
inst.ongoing_tokens += input_length
|
||
inst.pending_prefill_tokens += estimated_new
|
||
inst.num_requests += 1
|
||
|
||
async def generate():
|
||
prefill_done = False
|
||
try:
|
||
async with inst.client.stream("POST", api, json=req_data, headers=headers) as resp:
|
||
resp.raise_for_status()
|
||
async for chunk in resp.aiter_bytes():
|
||
if not prefill_done:
|
||
inst.pending_prefill_tokens -= estimated_new
|
||
inst.ongoing_decode_tokens += input_length
|
||
breakdown["t_first_token"] = _time.monotonic()
|
||
prefill_done = True
|
||
yield chunk
|
||
inst.record_prefix(token_ids)
|
||
finally:
|
||
if not prefill_done:
|
||
inst.pending_prefill_tokens -= estimated_new
|
||
else:
|
||
inst.ongoing_decode_tokens -= input_length
|
||
inst.ongoing_tokens -= input_length
|
||
inst.num_requests -= 1
|
||
breakdown["t_done"] = _time.monotonic()
|
||
_breakdown_log.append(breakdown)
|
||
|
||
return StreamingResponse(generate(), media_type="text/event-stream")
|
||
|
||
|
||
PREFILL_TIMEOUT_S = 120 # max seconds to wait for P-instance prefill
|
||
|
||
|
||
async def _handle_heavy_offload(api, req_data, headers, token_ids, input_length,
|
||
p_inst, d_inst, breakdown):
|
||
"""HEAVY request: prefill on p_inst (C_s), KV via Mooncake, decode on d_inst (D).
|
||
|
||
On prefill timeout/failure, falls back to co-located decode on d_inst.
|
||
"""
|
||
request_id = headers.get("X-Request-Id", "")
|
||
estimated_new = breakdown.get("estimated_new_tokens", 0)
|
||
# V2: p_inst is C_s with cache, so pending_prefill_tokens was incremented
|
||
# by estimated_new (only new tokens), not full input_length.
|
||
p_prefill_release = estimated_new
|
||
|
||
# Step 1: Await prefill on p_inst (ongoing_tokens already reserved by caller)
|
||
breakdown["t_prefill_sent"] = _time.monotonic()
|
||
prefill_ok = False
|
||
try:
|
||
prefill_data = req_data.copy()
|
||
prefill_data["kv_transfer_params"] = {
|
||
"do_remote_decode": True,
|
||
"do_remote_prefill": False,
|
||
"transfer_id": "xfer-" + request_id,
|
||
}
|
||
prefill_data["stream"] = False
|
||
prefill_data["max_tokens"] = 1
|
||
prefill_data.pop("max_completion_tokens", None)
|
||
prefill_data.pop("stream_options", None)
|
||
|
||
p_headers = {**headers, "X-data-parallel-rank": "0"}
|
||
resp = await asyncio.wait_for(
|
||
p_inst.client.post(api, json=prefill_data, headers=p_headers),
|
||
timeout=PREFILL_TIMEOUT_S,
|
||
)
|
||
resp.raise_for_status()
|
||
await resp.aclose()
|
||
p_inst.record_prefix(token_ids)
|
||
breakdown["t_prefill_done"] = _time.monotonic()
|
||
prefill_ok = True
|
||
except Exception as e:
|
||
breakdown["t_prefill_done"] = _time.monotonic()
|
||
breakdown["prefill_error"] = str(e)
|
||
finally:
|
||
# Always release P-instance resources exactly once
|
||
p_inst.ongoing_tokens -= input_length
|
||
p_inst.pending_prefill_tokens -= p_prefill_release
|
||
p_inst.num_requests -= 1
|
||
p_inst.active_p_offloads = max(0, p_inst.active_p_offloads - 1)
|
||
|
||
if not prefill_ok:
|
||
# Fallback: co-located prefill+decode on d_inst (no KV transfer)
|
||
breakdown["route_class"] = "HEAVY_COLO_FALLBACK"
|
||
d_inst.ongoing_tokens += input_length
|
||
d_inst.pending_prefill_tokens += estimated_new
|
||
d_inst.num_requests += 1
|
||
|
||
async def generate_fallback():
|
||
prefill_done = False
|
||
try:
|
||
async with d_inst.client.stream("POST", api, json=req_data, headers=headers) as resp:
|
||
resp.raise_for_status()
|
||
async for chunk in resp.aiter_bytes():
|
||
if not prefill_done:
|
||
d_inst.pending_prefill_tokens -= estimated_new
|
||
d_inst.ongoing_decode_tokens += input_length
|
||
breakdown["t_first_token"] = _time.monotonic()
|
||
prefill_done = True
|
||
yield chunk
|
||
d_inst.record_prefix(token_ids)
|
||
finally:
|
||
if not prefill_done:
|
||
d_inst.pending_prefill_tokens -= estimated_new
|
||
else:
|
||
d_inst.ongoing_decode_tokens -= input_length
|
||
d_inst.ongoing_tokens -= input_length
|
||
d_inst.num_requests -= 1
|
||
breakdown["t_done"] = _time.monotonic()
|
||
_breakdown_log.append(breakdown)
|
||
|
||
return StreamingResponse(generate_fallback(), media_type="text/event-stream")
|
||
|
||
# Step 2: Stream decode on d_inst (pulls KV from Mooncake)
|
||
d_inst.ongoing_tokens += input_length
|
||
d_inst.ongoing_decode_tokens += input_length
|
||
d_inst.num_requests += 1
|
||
breakdown["t_decode_sent"] = _time.monotonic()
|
||
|
||
parsed = urllib.parse.urlparse(str(p_inst.client.base_url))
|
||
bootstrap_addr = "http://%s:%s" % (parsed.hostname, p_inst.bootstrap_port)
|
||
|
||
decode_data = req_data.copy()
|
||
decode_data["kv_transfer_params"] = {
|
||
"do_remote_decode": False,
|
||
"do_remote_prefill": True,
|
||
"remote_bootstrap_addr": bootstrap_addr,
|
||
"remote_engine_id": p_inst.engine_id.get(0, ""),
|
||
"transfer_id": "xfer-" + request_id,
|
||
}
|
||
|
||
async def generate():
|
||
first_token = True
|
||
try:
|
||
async with d_inst.client.stream("POST", api, json=decode_data, headers=headers) as resp:
|
||
resp.raise_for_status()
|
||
async for chunk in resp.aiter_bytes():
|
||
if first_token:
|
||
breakdown["t_first_token"] = _time.monotonic()
|
||
first_token = False
|
||
yield chunk
|
||
finally:
|
||
d_inst.ongoing_tokens -= input_length
|
||
d_inst.ongoing_decode_tokens -= input_length
|
||
d_inst.num_requests -= 1
|
||
breakdown["t_done"] = _time.monotonic()
|
||
_breakdown_log.append(breakdown)
|
||
|
||
return StreamingResponse(generate(), media_type="application/json")
|
||
|
||
|
||
async def _send_prefill_async(p_inst, api, prefill_data, p_headers, token_ids,
|
||
input_length, breakdown):
|
||
"""Fire-and-forget prefill: send and don't block caller."""
|
||
try:
|
||
resp = await p_inst.client.post(api, json=prefill_data, headers=p_headers)
|
||
breakdown["t_prefill_done"] = _time.monotonic()
|
||
resp.raise_for_status()
|
||
await resp.aclose()
|
||
p_inst.record_prefix(token_ids)
|
||
except Exception:
|
||
breakdown["t_prefill_done"] = _time.monotonic()
|
||
breakdown["prefill_error"] = True
|
||
finally:
|
||
p_inst.ongoing_tokens -= input_length
|
||
|
||
|
||
async def _handle_pd_sep(api, req_data, request_id, token_ids, input_length,
|
||
session_id, headers):
|
||
"""PD-Sep mode with per-stage breakdown profiling."""
|
||
breakdown = {
|
||
"request_id": request_id,
|
||
"input_length": input_length,
|
||
"t_proxy_recv": _time.monotonic(),
|
||
}
|
||
|
||
p_inst, _ = pick_instance(prefill_instances, token_ids, session_id,
|
||
input_length, session_affinity)
|
||
d_inst = min(decode_instances, key=lambda x: x.ongoing_tokens)
|
||
breakdown["p_inst"] = p_inst.url
|
||
breakdown["d_inst"] = d_inst.url
|
||
|
||
prefill_data = req_data.copy()
|
||
prefill_data["kv_transfer_params"] = {
|
||
"do_remote_decode": True, "do_remote_prefill": False,
|
||
"transfer_id": f"xfer-{request_id}",
|
||
}
|
||
prefill_data["stream"] = False
|
||
prefill_data["max_tokens"] = 1
|
||
prefill_data.pop("max_completion_tokens", None)
|
||
prefill_data.pop("stream_options", None)
|
||
p_headers = {**headers, "X-data-parallel-rank": "0"}
|
||
|
||
p_inst.ongoing_tokens += input_length
|
||
breakdown["t_prefill_sent"] = _time.monotonic()
|
||
|
||
if global_args.fire_and_forget:
|
||
asyncio.create_task(_send_prefill_async(
|
||
p_inst, api, prefill_data, p_headers, token_ids, input_length, breakdown))
|
||
else:
|
||
try:
|
||
resp = await p_inst.client.post(api, json=prefill_data, headers=p_headers)
|
||
breakdown["t_prefill_done"] = _time.monotonic()
|
||
resp.raise_for_status()
|
||
await resp.aclose()
|
||
p_inst.record_prefix(token_ids)
|
||
except Exception as e:
|
||
breakdown["t_prefill_done"] = _time.monotonic()
|
||
breakdown["prefill_error"] = True
|
||
_breakdown_log.append(breakdown)
|
||
raise HTTPException(status_code=502, detail=f"Prefill failed: {e}")
|
||
finally:
|
||
p_inst.ongoing_tokens -= input_length
|
||
|
||
# Send decode
|
||
d_inst.ongoing_tokens += input_length
|
||
parsed = urllib.parse.urlparse(str(p_inst.client.base_url))
|
||
bootstrap_addr = f"http://{parsed.hostname}:{p_inst.bootstrap_port}"
|
||
|
||
decode_data = req_data.copy()
|
||
decode_data["kv_transfer_params"] = {
|
||
"do_remote_decode": False, "do_remote_prefill": True,
|
||
"remote_bootstrap_addr": bootstrap_addr,
|
||
"remote_engine_id": p_inst.engine_id.get(0, ""),
|
||
"transfer_id": f"xfer-{request_id}",
|
||
}
|
||
|
||
breakdown["t_decode_sent"] = _time.monotonic()
|
||
|
||
async def generate():
|
||
first_token = True
|
||
try:
|
||
async with d_inst.client.stream("POST", api, json=decode_data, headers=headers) as resp:
|
||
resp.raise_for_status()
|
||
async for chunk in resp.aiter_bytes():
|
||
if first_token:
|
||
breakdown["t_first_token"] = _time.monotonic()
|
||
first_token = False
|
||
yield chunk
|
||
finally:
|
||
breakdown["t_done"] = _time.monotonic()
|
||
d_inst.ongoing_tokens -= input_length
|
||
_breakdown_log.append(breakdown)
|
||
|
||
return StreamingResponse(generate(), media_type="application/json")
|
||
|
||
|
||
@app.get("/breakdown")
|
||
async def get_breakdown():
|
||
"""Return per-request breakdown data for analysis."""
|
||
return _breakdown_log
|
||
|
||
|
||
@app.get("/stats")
|
||
async def get_stats():
|
||
"""Return per-instance live state for debugging."""
|
||
instances = combined_instances or prefill_instances + decode_instances
|
||
return [{
|
||
"url": inst.url,
|
||
"role": "combined",
|
||
"ongoing_tokens": inst.ongoing_tokens,
|
||
"pending_prefill_tokens": inst.pending_prefill_tokens,
|
||
"ongoing_decode_tokens": inst.ongoing_decode_tokens,
|
||
"num_requests": inst.num_requests,
|
||
"active_p_offloads": inst.active_p_offloads,
|
||
"cached_blocks": len(inst.cached_blocks),
|
||
} for inst in instances]
|
||
|
||
|
||
def parse_args():
|
||
p = argparse.ArgumentParser(description="Unified cache-aware global scheduler")
|
||
p.add_argument("--port", type=int, default=8000)
|
||
p.add_argument("--host", type=str, default="0.0.0.0")
|
||
p.add_argument("--combined", nargs="+", help="Combined mode: list of instance URLs")
|
||
p.add_argument("--prefill", nargs="+", action="append", dest="prefill_raw",
|
||
help="PD-Sep prefill: URL [bootstrap_port]")
|
||
p.add_argument("--decode", nargs=1, action="append", dest="decode_raw",
|
||
help="PD-Sep decode: URL")
|
||
p.add_argument("--fire-and-forget", action="store_true",
|
||
help="Send prefill async, don't await before decode")
|
||
p.add_argument("--heavy-threshold", type=int, default=20000,
|
||
help="New tokens threshold for HEAVY classification (adaptive offload)")
|
||
p.add_argument("--offload", action="store_true",
|
||
help="Enable Mooncake KV offload for HEAVY requests (requires kv_both instances)")
|
||
p.add_argument("--bootstrap-ports", type=str, default="",
|
||
help="Comma-separated bootstrap ports for combined instances (for offload mode)")
|
||
p.add_argument("--policy", type=str, default="linear", choices=["linear", "lmetric"],
|
||
help="Routing policy: linear (default) or lmetric (P_tokens × BS, OSDI'26)")
|
||
p.add_argument("--overload-factor", type=float, default=2.0,
|
||
help="Break session affinity when instance load > factor * avg")
|
||
args = p.parse_args()
|
||
|
||
args.prefill = []
|
||
if args.prefill_raw:
|
||
for entry in args.prefill_raw:
|
||
url = entry[0]
|
||
bp = int(entry[1]) if len(entry) > 1 and entry[1].lower() != "none" else None
|
||
args.prefill.append((url, bp))
|
||
args.decode = [e[0] for e in (args.decode_raw or [])]
|
||
|
||
if not args.combined and not args.prefill:
|
||
p.error("Must specify either --combined or --prefill/--decode")
|
||
return args
|
||
|
||
|
||
if __name__ == "__main__":
|
||
global_args = parse_args()
|
||
HEAVY_THRESHOLD = global_args.heavy_threshold
|
||
OVERLOAD_FACTOR = global_args.overload_factor
|
||
uvicorn.run(app, host=global_args.host, port=global_args.port)
|