Adaptive Ticket Locking Sleep Duration Calculation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In multiprocessing systems, processes often waste CPU cycles while spinning for spinlocks, as the duration for sleeping when unable to secure a lock is unknown, leading to inefficiencies and potential delays when the lock is released.
Innovation Solution
An adaptive ticket locking mechanism that assigns sequential ticket numbers to processes, allowing them to spin for a predetermined number of cycles, calculate the sleep duration based on ticket processing rates, and sleep only if the estimated time exceeds a threshold, thereby optimizing CPU usage and minimizing overhead when reattempting to acquire the lock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If processes continuously spin for spinlocks, then they can immediately acquire the lock when available, but CPU cycles are wasted and system efficiency decreases
Solution Approach 1:
The patent implements periodic action by having processes alternate between spinning and sleeping in cycles. Instead of continuously spinning, processes spin for a predetermined number of CPU cycles, then sleep for a calculated duration based on ticket processing rates, and repeat this periodic pattern until the lock is acquired. This resolves the contradiction by maintaining lock acquisition capability while eliminating continuous CPU waste.
Solution Approach 2:
The patent applies dynamics by making the sleep duration adaptive rather than fixed. The sleep duration is dynamically calculated based on the ticket processing rate observed during spinning cycles and the number of tickets remaining. This allows the system to adapt to varying load conditions, optimizing the balance between immediate lock acquisition and CPU cycle conservation.
2Loss of energy
If processes sleep for extended periods when unable to secure a lock, then CPU usage is optimized, but the time to acquire the lock increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the ticket processing rate during spinning cycles and using this information to adjust the sleep duration. The system observes how many tickets are processed per CPU cycle, calculates the remaining wait time based on tickets ahead in the queue, and adjusts the sleep period accordingly. This feedback mechanism ensures processes sleep long enough to save CPU cycles but not so long as to unnecessarily delay lock acquisition.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the sleep duration parameter based on system conditions. Rather than using a fixed sleep time, the system changes the sleep parameter adaptively based on the observed ticket processing rate and queue position, optimizing the trade-off between CPU utilization and lock acquisition time.
3Productivity
If processes calculate and sleep based on estimated lock availability, then CPU efficiency improves, but system complexity increases
Solution Approach 1:
The patent applies self-service by having processes autonomously calculate their own sleep duration based on information they can obtain themselves (ticket number, observed processing rate). Each process independently determines when to spin and when to sleep without requiring complex centralized control, reducing system complexity while maintaining productivity benefits.
Solution Approach 2:
The patent implements preliminary action by having processes perform a brief spinning phase to observe the ticket processing rate before calculating and entering the sleep state. This preliminary observation period provides the data needed for accurate sleep duration calculation, enabling efficient CPU utilization without requiring complex pre-computation or external information.
Data Source
AI summary
A computational device maintains a spinlock for exclusive access of a resource by a process of a plurality of processes. In response to determining by the process that a turn for securing the spinlock has not arrived for the process, a sleep duration is determined for the process, prior to making a next attempt to secure the spinlock.