Operational Remediation Reports

Lock Guard Remediation Report

Acquire a guard lock without blocking and turn the count of waiters into an enter, backoff, or page remediation action.

guard contention A nonblocking `threading.Lock` acquire plus a deterministic waiter count selects whether to enter, back off, or page, without depending on scheduler timing.

Lock Guard Remediation Report

waiters
lock_guard_remediation_report.py
Replay: real traced execution (multi-file project)
import threading


waiters = 0
guard = threading.Lock()
held = 1 if guard.acquire(blocking=False) else 0
backoff_limit = 2

action = "enter" if waiters == 0 else "backoff" if waiters <= backoff_limit else "page"

if held:
    guard.release()

print("waiters=" + str(waiters) + " held=" + str(held) + " action=" + action)

import threading


waiters = 1
guard = threading.Lock()
held = 1 if guard.acquire(blocking=False) else 0
backoff_limit = 2

action = "enter" if waiters == 0 else "backoff" if waiters <= backoff_limit else "page"

if held:
    guard.release()

print("waiters=" + str(waiters) + " held=" + str(held) + " action=" + action)

import threading


waiters = 3
guard = threading.Lock()
held = 1 if guard.acquire(blocking=False) else 0
backoff_limit = 2

action = "enter" if waiters == 0 else "backoff" if waiters <= backoff_limit else "page"

if held:
    guard.release()

print("waiters=" + str(waiters) + " held=" + str(held) + " action=" + action)

  1. waiters ← 0, guard ← ⟨unlocked _thread.lock A⟩, held ← 1, backoff_limit ← 2

    4waiters→ 0 = 0  #@waiters=1, 35guard→ ⟨unlocked _thread.lock A⟩ = threading<module 'threading' from '/usr/local/lib/python3.12/threading.py'>.Lock()6held→ 1 = 1 if guard→ ⟨locked _thread.lock A⟩.acquire(blocking=False) else 07backoff_limit→ 2 = 289action→ enter = "enter" if waiters0 == 0 else "backoff" if waiters <= backoff_limit2 else "page"

  2. guard ← ⟨unlocked _thread.lock A⟩

    11if held1:12    guard→ ⟨unlocked _thread.lock A⟩.release()

  3. print("waiters=" + str(waiters) + " held=" + str(held) + " action=" + …

    14print("waiters=" + str(waiters0) + " held=" + str(held1) + " action=" + actionenter)
    outputwaiters=0 held=1 action=enter

  1. waiters ← 1, guard ← ⟨unlocked _thread.lock A⟩, held ← 1, backoff_limit ← 2

    4waiters→ 1 = 15guard→ ⟨unlocked _thread.lock A⟩ = threading<module 'threading' from '/usr/local/lib/python3.12/threading.py'>.Lock()6held→ 1 = 1 if guard→ ⟨locked _thread.lock A⟩.acquire(blocking=False) else 07backoff_limit→ 2 = 289action→ backoff = "enter" if waiters1 == 0 else "backoff" if waiters <= backoff_limit2 else "page"

  2. guard ← ⟨unlocked _thread.lock A⟩

    11if held1:12    guard→ ⟨unlocked _thread.lock A⟩.release()

  3. print("waiters=" + str(waiters) + " held=" + str(held) + " action=" + …

    14print("waiters=" + str(waiters1) + " held=" + str(held1) + " action=" + actionbackoff)
    outputwaiters=1 held=1 action=backoff

  1. waiters ← 3, guard ← ⟨unlocked _thread.lock A⟩, held ← 1, backoff_limit ← 2

    4waiters→ 3 = 35guard→ ⟨unlocked _thread.lock A⟩ = threading<module 'threading' from '/usr/local/lib/python3.12/threading.py'>.Lock()6held→ 1 = 1 if guard→ ⟨locked _thread.lock A⟩.acquire(blocking=False) else 07backoff_limit→ 2 = 289action→ page = "enter" if waiters3 == 0 else "backoff" if waiters <= backoff_limit2 else "page"

  2. guard ← ⟨unlocked _thread.lock A⟩

    11if held1:12    guard→ ⟨unlocked _thread.lock A⟩.release()

  3. print("waiters=" + str(waiters) + " held=" + str(held) + " action=" + …

    14print("waiters=" + str(waiters3) + " held=" + str(held1) + " action=" + actionpage)
    outputwaiters=3 held=1 action=page