Files
sglang/python/sglang/srt/utils/watchdog.py
2026-01-04 00:28:32 -08:00

162 lines
4.7 KiB
Python

from __future__ import annotations
import logging
import signal
import sys
import threading
import time
from contextlib import contextmanager
from typing import Callable, Optional
import psutil
from sglang.srt.utils.common import pyspy_dump_schedulers
logger = logging.getLogger(__name__)
class Watchdog:
@staticmethod
def create(
debug_name: str,
watchdog_timeout: Optional[float],
soft: bool = False,
test_stuck_time: float = 0,
) -> Watchdog:
if watchdog_timeout is None:
assert (
test_stuck_time == 0
), f"stuck tester can be enabled only if soft watchdog is enabled."
return _WatchdogNoop()
return _WatchdogReal(
debug_name=debug_name,
watchdog_timeout=watchdog_timeout,
soft=soft,
test_stuck_time=test_stuck_time,
)
def feed(self):
pass
@contextmanager
def disable(self):
yield
class _WatchdogReal(Watchdog):
def __init__(
self,
debug_name: str,
watchdog_timeout: float,
soft: bool = False,
test_stuck_time: float = 0,
):
self._counter = 0
self._active = True
self._test_stuck_time = test_stuck_time
self._test_stuck_triggered = False
self._raw = WatchdogRaw(
debug_name=debug_name,
get_counter=lambda: self._counter,
is_active=lambda: self._active,
watchdog_timeout=watchdog_timeout,
soft=soft,
)
logger.info(f"Watchdog {self._raw.debug_name} initialized.")
if self._test_stuck_time > 0:
logger.info(
f"Watchdog {self._raw.debug_name} is configured to use {test_stuck_time=}."
)
def feed(self):
# Only trigger the test stuck behavior once to avoid blocking server
# startup health checks while still testing watchdog timeout detection
if self._test_stuck_time > 0 and not self._test_stuck_triggered:
self._test_stuck_triggered = True
logger.info(
f"Watchdog {self._raw.debug_name} start deliberately stuck for {self._test_stuck_time}s"
)
time.sleep(self._test_stuck_time)
logger.info(
f"Watchdog {self._raw.debug_name} end deliberately stuck for {self._test_stuck_time}s"
)
self._counter += 1
@contextmanager
def disable(self):
assert self._active
self._active = False
try:
yield
finally:
assert not self._active
self._active = True
class _WatchdogNoop(Watchdog):
pass
class WatchdogRaw:
def __init__(
self,
debug_name: str,
get_counter: Callable[[], int],
is_active: Callable[[], bool],
watchdog_timeout: float,
soft: bool = False,
dump_info: Optional[Callable[[], str]] = None,
):
self.debug_name = debug_name
self.get_counter = get_counter
self.is_active = is_active
self.watchdog_timeout = watchdog_timeout
self.soft = soft
self.dump_info = dump_info
self.parent_process = psutil.Process().parent()
t = threading.Thread(target=self._watchdog_thread, daemon=True)
t.start()
def _watchdog_thread(self):
try:
while True:
self._watchdog_once()
except Exception as e:
logger.error(
f"{self.debug_name} watchdog thread crashed: {e}", exc_info=True
)
def _watchdog_once(self):
watchdog_last_counter = 0
watchdog_last_time = time.perf_counter()
while True:
current = time.perf_counter()
if self.is_active():
current_counter = self.get_counter()
if watchdog_last_counter == current_counter:
if current > watchdog_last_time + self.watchdog_timeout:
break
else:
watchdog_last_counter = current_counter
watchdog_last_time = current
time.sleep(self.watchdog_timeout / 2)
if self.dump_info is not None and (info_msg := self.dump_info()):
logger.error(f"{self.debug_name} debug info:\n{info_msg}")
pyspy_dump_schedulers()
logger.error(
f"{self.debug_name} watchdog timeout "
f"({self.watchdog_timeout=}, {self.soft=})"
)
print(file=sys.stderr, flush=True)
print(file=sys.stdout, flush=True)
if not self.soft:
# Wait for some time so that the parent process can print the error.
time.sleep(5)
self.parent_process.send_signal(signal.SIGQUIT)