python / python/cpython

Issues in asyncio documentation section "A homemade asyncio.sleep"

未關閉
#143,727 6 則留言 0 個 reaction 已指派 1 人 在 GitHub 檢視

@willingc 已經在處理了。

開始於 2026年7月23日。

  • #143850 來自 @anordin95 —— 未關閉
docs topic-asyncio
主要語言
Python
星號
77.2k
分支
36k
PR 合併指標
PR 指標待擷取

描述

Documentation

Link to section:
https://docs.python.org/3/howto/a-conceptual-overview-of-asyncio.html#a-homemade-asyncio-sleep

From my perspective, there are two issues in this section:

  1. Creating a task for the sleep call in main (await asyncio.create_task(async_sleep(3))) hides if the implementation actually cedes control to the event loop as desired or if it blocks it - an implementation using time.sleep(seconds) would also behave sane here. Therefore, I think it should be changed to await async_sleep(3).
  2. The implementation is said to mimick asyncio.sleep(), which can make readers think that this could actually be a usable replacement that behaves similarly. However, in one crucial aspect it behaves the opposite way: It causes 100% CPU usage on one core due to the busy waiting approach, which is opposed to how a sleep should behave. Two options I see:
  • Add something like: "Note: This implementation uses busy waiting and will consume 100% CPU on one core, unlike the real asyncio.sleep(). This implementation is purely meant for educational purposes to demonstrate futures and event loop interaction."
  • Add a synchronous time.sleep(0.001) or such right before await YieldToEventLoop() (in both example implementations) and explain (trade-off, sub-optimal workaround, will cause undesired CPU usage but significantly less than without).
Linked PRs
  • gh-143850

貢獻指南

開啟貢獻指南

從這裡開始

  1. 先讀完整個 Issue,再讀專案的貢獻指南。
  2. 在 Issue 下留言說明你要接手 —— 這能避免兩個人做同樣的事。
  3. Fork 儲存庫,在一個分支上完成修改。
  4. 送出 Pull Request,並在描述裡引用這個 Issue 編號。

評估

這個 Issue 還沒有評估資料。

把新 issue 寄到你的電子郵件信箱

精選適合新手參與的 GitHub issue 摘要。