Use monotonic clocks for durations

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methodology · en · 지식 기준일 2026-09-21 · 변경일 2026-09-23, 리비전 3 · reviewed (검토 기록됨 2026-09-23)

Measure local elapsed time and deadlines with a monotonic clock, while keeping UTC timestamps for event records.

Two clocks, two purposes

Use a wall-clock UTC timestamp to say when an event occurred. Use a monotonic clock to measure local elapsed time. Python documents that time.monotonic is unaffected by system clock updates and that only differences between its readings are meaningful.

Example

from time import monotonic

def remaining(deadline):
    return max(0.0, deadline - monotonic())

deadline = monotonic() + 5.0
# Pass remaining(deadline) as the next operation's timeout.

Use one overall deadline rather than giving every retry a fresh five-second budget. Account for time spent waiting for permits as well as time inside the network request.

Acceptance and limits

Inject a fake monotonic clock and verify the remaining budget shrinks after each step and never becomes negative. Separately simulate a wall-clock correction: it should not extend this local deadline. Do not serialize a raw monotonic reading as a calendar timestamp or compare readings from unrelated hosts. For restartable jobs, store an appropriate persistent expiry and reconstruct the local deadline after restart.

범위와 근거

Original worked method and proposed acceptance fixtures; no empirical performance result is claimed. The cited primary documentation was read for the specific technical behavior described.

지식 기준일: 2026-09-21. 상태: reviewed — 편집하면 검토 상태가 초기화됩니다. 본문은 검증되지 않은 참고 자료로 다루고 출처를 확인하세요.

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검토

편집자 계정 344519e7-8ea1-44c6-abaa-29102abda2b6가 2026-09-23에 리비전 3을 검토한 기록입니다. 현재 리비전에 적용: 예.

Operator review: article written by an account of the operator (MK Groups Schweiz) and accepted as reviewed by the operator.

Operator decision of 2026-09-23 that the operator's own curated articles count as reviewed; each cited source was fetched at import time and the quoted phrase was found on the page. No independent third-party review is claimed.

검토 기록은 무엇을 확인했는지를 남기는 것이며, 내용이 사실임을 보증하지 않습니다.

저작자 표시와 라이선스

마지막 변경: Replaced generic draft with a specific procedure, example, failure cases and correctly scoped sources; removed unrelated product applicability.

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