Stacked Memory PE Dispatch Queues for Barrier-Aware Command Ordering
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Solution Overview
Problem
Existing systems face delays and inefficiencies due to unmanaged command dependencies in stacked memory architectures, leading to increased latency and incorrect results in high-performance computing applications.
Innovation Solution
A processing element (PE) architecture with multiple dispatch queues and a dispatcher that manages command execution based on type and completion status, ensuring proper ordering and execution of commands to maintain data dependencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If commands are executed in sequential order without managing dependencies, then processing speed increases, but incorrect results occur due to violated data dependencies
Solution Approach 1:
The system dynamically adjusts command execution ordering based on dependency relationships. The reorder buffer monitors completion status of prerequisite commands and dynamically reorders subsequent commands to maintain correct data dependencies while maximizing parallel execution. This resolves the contradiction by making the execution order flexible rather than fixed, allowing both speed and correctness.
Solution Approach 2:
The reorder buffer acts as an intermediary between the command submission queue and execution units. It receives commands, holds them temporarily, and releases them in the correct order based on dependency completion. This intermediary structure enables parallel processing while ensuring correctness by mediating the execution sequence.
2Reliability
If multiple commands are held at the submission queue waiting for barrier completion, then data dependency correctness is maintained, but latency increases
Solution Approach 1:
Instead of statically holding all commands after a barrier, the system dynamically determines when each command can be executed based on real-time completion status of prerequisite commands. The reorder buffer continuously monitors and adjusts execution timing, releasing commands as soon as their dependencies are satisfied, thereby minimizing latency while maintaining correctness.
Solution Approach 2:
The system performs preliminary tracking of command completion status and dependency relationships before executing subsequent commands. By preparing the execution schedule in advance based on known dependencies and monitoring completions, the system reduces waiting time compared to holding all commands until absolute certainty of barrier completion.
3Device complexity
If a simple single dispatch queue is used, then device complexity is reduced, but resource utilization decreases due to unmanaged command dependencies
Solution Approach 1:
The system uses a single physical dispatch queue but implements dynamic ordering logic that adapts to dependency requirements. The reorder buffer provides the intelligence to manage complex dependencies while using a simple queue structure, achieving high resource utilization without increasing physical complexity.
Solution Approach 2:
The single dispatch queue serves multiple functions: it acts as both a submission buffer and an execution schedule, while the reorder buffer provides dependency management for all command types. This multi-functional approach achieves complex dependency management with minimal structural complexity.
Data Source
AI summary
Provided are systems, methods, and apparatuses of program execution in a processing element (PE). In one or more examples, the systems, devices, and methods include executing software code at a processing element (PE) of a stacked memory module; pushing, via a dispatcher of the PE, a first command of the software code from a submission queue to a first dispatch queue, the PE comprising multiple dispatch queues that include the first dispatch queue; pushing, via the dispatcher, a barrier command of the software code from the submission queue to the first dispatch queue; holding a second command of the software code at the submission queue based on the barrier command; and pushing the second command from the submission queue to the first dispatch queue based on the dispatcher determining that the first dispatch queue is empty.