Files
ComfyAssets-ComfyUI_PromptM…/utils/parallel.py
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Vito 7e11d9cae2 Protected rows (#586), review-bot fixes (#593) and LoRA cancel tests (#575) (#597)
* test(lora): hold the import job to test cancel before and after the commit (#575)

Squashed from PR #594. Closes #575.

* fix: address review-bot findings on merged PRs (#593)

Squashed from PR #595. Closes #593.

* fix(maintenance): list every protected item with its reason (#586)

Squashed from PR #596. Closes #586.
2026-11-01 06:42:12 +00:00

191 lines
7.6 KiB
Python

"""Bounded thread-pool map for the long jobs (output scan, thumbnails).
Threads, not processes: this code runs inside ComfyUI's server, where forking
a CUDA-initialised, multi-threaded process is unsafe and the spawn start
method would re-import ComfyUI's main module in every child. Pillow releases
the GIL while decoding, resizing and encoding, so threads still scale close
to linearly for both jobs.
Interpreter exit (#375): ``threading._shutdown`` shuts every thread pool
(``submit`` then raises "cannot schedule new futures after interpreter
shutdown") before it joins the non-daemon threads and long before the package
teardown runs, while our daemon threads keep working. Measured on 3.12 and
3.14, ``Thread.start`` still succeeds in that window; it is refused ("can't
create new thread at interpreter shutdown") only once the interpreter is
marked finalizing, after the ``atexit`` callbacks. ``refused_at_shutdown``
recognises both; ``note_refusal`` logs one DEBUG line per place, with no
traceback.
One long-lived pool (#523): every ``map_parallel`` call shares one pool of
``workers`` threads (``JOB_THREAD_PREFIX``), kept between jobs, instead of a
new pool per call. Image work then reuses the same few threads, and their
malloc arenas, rather than leaving each call's image-sized buffers in a new
set of arenas. A different ``workers`` count (the Worker threads setting
changed) replaces the pool; the old one finishes what it holds and exits.
``shutdown_job_pool`` stops it (the package teardown); the next call starts
a fresh one.
"""
import logging
import threading
import time
from concurrent.futures import ThreadPoolExecutor, wait
from .exit_signal import checked
SHUTDOWN_REFUSAL = "interpreter shutdown"
# ``submit`` on a pool already shut down (this module's teardown or a resize).
SHUT_POOL_REFUSAL = "after shutdown"
JOB_THREAD_PREFIX = "pm-worker"
# The package teardown's bound for the job threads to finish their item.
JOB_POOL_JOIN_SECONDS = 5
_logger = logging.getLogger("prompt_manager.parallel")
_noted = set()
_noted_lock = threading.Lock()
_pool_lock = threading.Lock()
_pool = None # (workers, ThreadPoolExecutor)
_retired = [] # pools replaced by a new size, finishing what they hold
def refused_at_shutdown(error):
"""Whether ``error`` is a thread or pool start refused at interpreter exit."""
return isinstance(error, RuntimeError) and SHUTDOWN_REFUSAL in str(error)
def note_refusal(logger, what):
"""Log once per ``what``, at DEBUG and without a traceback, that ``what``
was refused because the interpreter is exiting."""
key = (logger.name, what)
with _noted_lock:
if key in _noted:
return
_noted.add(key)
logger.debug(f"{what}: refused, the interpreter is exiting")
def job_pool_started():
"""Whether a job pool exists (the teardown stops it)."""
return _pool is not None or bool(_retired)
def _job_pool(workers):
"""The shared pool of ``workers`` threads, replacing one of another size."""
global _pool
with _pool_lock:
if _pool is not None and _pool[0] == workers:
return _pool[1]
retired = _pool
_pool = (
workers,
ThreadPoolExecutor(workers, thread_name_prefix=JOB_THREAD_PREFIX),
)
current = _pool[1]
if retired is not None:
retired[1].shutdown(wait=False) # it still runs what it holds
with _pool_lock:
_retired[:] = [p for p in _retired if _alive(p)] + [retired[1]]
return current
def shutdown_job_pool(timeout=None):
"""Stop the job pool (and any pool a resize retired): queued items are
cancelled (their callers run them on their own thread), running ones are
joined up to ``timeout`` seconds. True when no job thread is left."""
global _pool
with _pool_lock:
current, _pool = _pool, None
executors = _retired[:] + ([] if current is None else [current[1]])
_retired.clear()
threads = []
for executor in executors:
# After shutdown: it takes the lock ``submit`` holds while it starts
# and records a thread, so every thread is listed and none starts.
executor.shutdown(wait=False, cancel_futures=True)
threads.extend(getattr(executor, "_threads", ()))
deadline = None if timeout is None else time.monotonic() + timeout
for thread in threads:
thread.join(None if deadline is None else max(0.0, deadline - time.monotonic()))
return not any(thread.is_alive() for thread in threads)
def _alive(executor):
return any(t.is_alive() for t in getattr(executor, "_threads", ()))
def _forget(executor):
"""Drop *executor* as the shared pool (a later call starts a new one)."""
global _pool
with _pool_lock:
if _pool is not None and _pool[1] is executor:
_pool = None
def _on_job_thread():
return threading.current_thread().name.startswith(JOB_THREAD_PREFIX + "_")
def map_parallel(func, items, workers):
"""Apply ``func`` to every item on the shared pool of ``workers``
threads, keeping order.
``workers`` below 1 counts as 1. A call made from a job thread runs on
that thread, so nested work never waits for its own pool. An exception
in ``func`` propagates to the caller once the call's other items have
stopped (those not started are dropped), so callers that must survive
bad input wrap ``func`` themselves. A pool refused at interpreter exit
runs the items it did not start on the calling thread (#375). An item
that has not started when the interpreter starts exiting raises
ExitRequested instead (#376).
"""
func = checked(func)
items = list(items)
if not items or _on_job_thread():
return [func(item) for item in items]
pool = _job_pool(max(1, int(workers or 1)))
futures = []
try:
for item in items:
futures.append(pool.submit(func, item))
except RuntimeError as error:
if refused_at_shutdown(error):
note_refusal(_logger, "A worker pool")
# Drop what was queued but not started; it runs here instead.
# (A refused Thread.start leaves its item queued without a future
# here: it is cancelled too, unless a busy pool thread took it in
# between, the one case where an item can run twice.)
_forget(pool)
pool.shutdown(wait=False, cancel_futures=True)
elif SHUT_POOL_REFUSAL not in str(error):
raise
return _collect(func, items, futures)
def _collect(func, items, futures):
"""``_run_rest``; on an error, first drop the call's items not started
and wait for its running ones, as the old per-call pool's exit did."""
try:
return _run_rest(func, items, futures)
except BaseException: # re-raised below, after the running items stop
# Wait only for what could not be cancelled (running or done). A
# future ``shutdown(cancel_futures=True)`` already cancelled stays
# CANCELLED, never notified, and ``wait`` would block on it forever
# (#593); ``cancel()`` is True for those as well.
wait([future for future in futures if not future.cancel()])
raise
def _run_rest(func, items, futures):
"""The pool's finished results, and every item it did not run, run here.
After ``shutdown(cancel_futures=True)`` each submitted future either ran
(its result or exception is kept) or was cancelled before it started.
"""
results = []
for index, item in enumerate(items):
future = futures[index] if index < len(futures) else None
if future is not None and not future.cancelled():
results.append(future.result())
else:
results.append(func(item))
return results