State-Based Queue Protocol for Lock-Free Ring Buffer
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Solution Overview
Problem
Traditional queue management techniques are sub-optimal in high-performance computing environments, leading to significant performance issues due to record locking schemes that take time to establish and predict, causing inefficiencies and wait/retry processes among competing threads.
Innovation Solution
A state-based queue protocol using atomic operations to change the record header, allowing threads to determine the state of records and update them without collisions, enabling lock-free access and minimizing wait operations by advancing to next-available records.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If record locking schemes are used to ensure proper queue management, then data integrity is maintained, but processing time increases significantly due to lock establishment and waiting
Solution Approach 1:
The patent extracts the locking mechanism entirely from the queue access protocol. Instead of using traditional locks to ensure data integrity, the system uses a lock-free ring buffer where each record contains state bits that atomically indicate availability. This removes the time-consuming lock establishment and waiting processes while maintaining reliability through atomic state transitions.
Solution Approach 2:
The patent replaces the mechanical locking system with an atomic state-based system. Rather than acquiring and releasing locks on records, threads perform atomic read-modify-write operations on state bits within record headers. This substitution eliminates the overhead of lock management while preserving data integrity through atomic operations that prevent race conditions.
2Ease of operation
If traditional record locking is implemented, then queue access is controlled, but system performance deteriorates due to wait/retry processes among competing threads
Solution Approach 1:
The patent implements a self-service mechanism where each thread independently determines record availability by checking state bits and autonomously transitions records to/from available states through atomic operations. This eliminates the need for threads to wait for or negotiate with locks held by other threads, thereby maintaining ease of access control while dramatically improving system performance by removing wait/retry cycles.
Solution Approach 2:
The patent performs preliminary actions by pre-establishing atomic state bits in each record header that indicate availability before any access attempt. Threads check these pre-existing state bits to determine if records are available, eliminating the need for preliminary lock acquisition. This preliminary state preparation enables immediate access decisions without performance-penalizing wait processes.
3Reliability
If locks are used to reserve queue locations, then concurrent access is managed, but it becomes unclear how long records are reserved, causing inefficiencies in lock checking
Solution Approach 1:
The patent uses state bits in record headers as visual indicators (analogous to color changes) that immediately show the availability status of each record. Threads can instantly determine if a record is available by checking the state bit value, eliminating the need to infer or track lock duration. This state indication mechanism provides complete information about record status without losing time-related information, as the state itself encodes availability rather than requiring separate timing tracking.
Data Source
AI summary
Methods and systems for execution of data operations in a queue are described. One method includes loading a pointer to a record in a lock-free ring buffer by an executing thread, as well as calculating an index from the pointer to a record to be processed and obtaining a header of the record to be processed. Based on the header, a state of the record to be processed is determined from among: a filled state, a filling state, a drained state, and a draining state. A candidate header is created which includes an updated state indicating that the record is in use by the executing thread. An atomic operation is performed to update the header of the record to the candidate header. Upon successful completion of the atomic operation to update the header of the record to the candidate header, a data operation is performed on the record.