Files
ComfyAssets-ComfyUI_PromptM…/utils/parallel.py
T
Vito Sansevero b98c716b48 feat: worker-thread setting speeds up the output scan and thumbnail generation
Both jobs processed one file at a time on a single core. Pillow decodes the
whole image to reach trailing PNG text chunks and releases the GIL while it
does, so a bounded thread pool scales almost linearly: on a 1 GB sample of
400 PNGs the metadata pass dropped from 18 s to 2.5 s at 8 threads, and 120
thumbnails from 4.6 s to 0.6 s.

- utils/parallel.py: map_parallel(func, items, workers) keeps order, runs on
  the caller's thread when workers is 1, and caps the pool at the item count
- PromptManagerConfig.WORKER_THREADS defaults to half the detected cores,
  is clamped to max_worker_threads() when loaded from config.json, and is
  persisted under "performance"
- settings API returns worker_threads and cpu_count and validates saves;
  the settings modal gets a "Worker threads" slider capped at the core count
- the scan reads each metadata batch on the configured threads; thumbnail
  generation processes batches of files per executor job, still emitting
  one progress event per file

Threads rather than processes: this runs inside ComfyUI's server, where
forking a CUDA-initialised process is unsafe and the spawn start method
would re-import ComfyUI's main module in every child.
2026-10-08 18:01:34 -07:00

27 lines
1.1 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.
"""
from concurrent.futures import ThreadPoolExecutor
def map_parallel(func, items, workers):
"""Apply ``func`` to every item on up to ``workers`` threads, keeping order.
``workers`` of 1 (or fewer) runs on the calling thread with no pool. An
exception in ``func`` propagates to the caller, so callers that must
survive bad input wrap ``func`` themselves.
"""
items = list(items)
workers = max(1, int(workers or 1))
if workers == 1 or len(items) <= 1:
return [func(item) for item in items]
max_workers = min(workers, len(items))
with ThreadPoolExecutor(max_workers, thread_name_prefix="pm-worker") as pool:
return list(pool.map(func, items))