python / python/cpython

pickle.load() significantly slows down with each call on Windows11 but not on Linux

未关闭
#117,545 2 条评论 1 个 reaction 已指派 0 人 在 GitHub 查看

还没有人认领这个 Issue。

OS-windows performance type-bug
主要语言
Python
星标
77.2k
派生
36k
PR 合并指标
PR 指标待抓取

描述

Bug report

Bug description:

My task is to read millions of numpy images and get a region dynamically. The application dictates that the images are stored in batches of about 3000 to 6000 in files. These files contain a pickled dict of numpy arrays. On Windows, reading gets dramatically slower with each call, see logs below. These logs are run on two laptops with completely identical hardware, including 40GB of RAM. While Windows is much slower anyways, it should not get slower with each call?

import os
import pickle
import time
import platform
import sys

import numpy as np
import psutil

filePath = r'C:\images.pkl'

print(f"Versions: {platform.system()=}, {platform.release()=}, {platform.version()=}, {sys.version=}, {np.__version__=}")

imagesDict = {i: np.random.randint(0, 255, (300, 300), dtype=np.uint8) for i in range(4000)}
with open(filePath, 'wb') as file:
    pickle.dump(imagesDict, file, pickle.HIGHEST_PROTOCOL)


thumbs = []
num_image_sets = 0
durations_s_sum = 0.
for i in range(500):
    start_s = time.perf_counter()
    with open(filePath, 'rb') as file:
        imagesDict: dict[int, np.ndarray] = pickle.load(file)
        for key in imagesDict.keys():
            image = imagesDict[key]
            thumb = image[:50, :50].copy()
            thumbs.append(thumb)

    durations_s_sum += (time.perf_counter() - start_s)
    num_image_sets += 1
    if 50 <= num_image_sets:
        memory_info = psutil.Process(os.getpid()).memory_info()
        print(f"{durations_s_sum:4.1f}s for 50 pickle files, rss={memory_info.rss/1024/1024:6,.0f}MB, vms={memory_info.vms/1024/1024:6,.0f}MB")
        durations_s_sum = 0.
        num_image_sets = 0
Windows 11
# Versions: platform.system()='Windows', platform.release()='10', platform.version()='10.0.22631', sys.version='3.11.5 | packaged by Anaconda, Inc. | (main, Sep 11 2023, 13:26:23) [MSC v.1916 64 bit (AMD64)]', np.__version__='1.26.3'
# 11.7s for 50 pickle files, rss= 1,211MB, vms= 1,215MB
# 11.8s for 50 pickle files, rss= 1,492MB, vms= 1,499MB
# 13.8s for 50 pickle files, rss= 2,272MB, vms= 2,302MB
# 15.7s for 50 pickle files, rss= 2,802MB, vms= 2,845MB
# 18.3s for 50 pickle files, rss= 3,328MB, vms= 3,383MB
# 21.0s for 50 pickle files, rss= 3,837MB, vms= 3,905MB
# 25.6s for 50 pickle files, rss= 4,369MB, vms= 4,448MB
# 28.0s for 50 pickle files, rss= 4,898MB, vms= 4,989MB
# 32.3s for 50 pickle files, rss= 5,427MB, vms= 5,530MB
# 36.7s for 50 pickle files, rss= 5,966MB, vms= 6,081MB
Linux
# Versions: platform.system()='Linux', platform.release()='6.0.12-76060012-generic', platform.version()='#202212290932~1674066459~20.04~3cd2bf3-Ubuntu SMP PREEMPT_DYNAMI', sys.version='3.10.9 (main, Jan 11 2023, 15:21:40) [GCC 11.2.0]', np.__version__='1.23.5'
#  2.8s for 50 pickle files, rss= 1,222MB, vms= 2,229MB
#  2.8s for 50 pickle files, rss= 1,730MB, vms= 2,738MB
#  2.8s for 50 pickle files, rss= 2,238MB, vms= 3,246MB
#  2.8s for 50 pickle files, rss= 2,747MB, vms= 3,754MB
#  2.8s for 50 pickle files, rss= 3,255MB, vms= 4,263MB
#  2.8s for 50 pickle files, rss= 3,764MB, vms= 4,772MB
#  2.8s for 50 pickle files, rss= 4,272MB, vms= 5,280MB
#  2.8s for 50 pickle files, rss= 4,780MB, vms= 5,789MB
#  2.9s for 50 pickle files, rss= 5,288MB, vms= 6,298MB
#  2.9s for 50 pickle files, rss= 5,797MB, vms= 6,806MB
CPython versions tested on:

3.11

Operating systems tested on:

Windows

贡献指南

打开贡献指南

从这里开始

  1. 先读完整个 Issue,再读项目的贡献指南。
  2. 在 Issue 下留言说明你要接手 —— 这能避免两个人做同样的事。
  3. Fork 仓库,在一个分支上完成修改。
  4. 提交 Pull Request,并在描述里引用这个 Issue 编号。

调研方向

该 issue 没有列出任何仓库文件或测试;首先,在报告的版本上于 Windows 和 Linux 中运行所提供的 pickle.load() reproducer,同时监控耗时和内存使用情况。完成标准是解释 Windows 上逐渐变慢的原因,并通过回归覆盖来处理这一问题。

由索引模型根据 Issue 内容生成。

评估

技术栈
numpy, python
领域
operating-systems, performance
Issue 类型
缺陷
难度
4/5
预计耗时
3-5 天
活跃度
停滞
描述清晰度
需要澄清
新手友好度
35/100

把新 issue 发到你的邮箱

精选适合新手参与的 GitHub issue 摘要。