Out-of-Order Accelerator Invocation With Register-Based Results
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Central Processing Units (CPUs) face inefficiencies due to their sequential programming model, which limits parallelism and requires high control overhead, making it challenging to scale compute and memory throughput, and conventional accelerator communication methods restrict out-of-order execution and control over tasks, leading to serialized and speculative limitations.
Innovation Solution
Implementing near-core accelerators (NCAs) that are directly controlled by the CPU core, using accelerator task instructions that execute speculatively and out-of-order, with results stored in CPU registers, allowing tighter control over task execution and enabling micro-threaded operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional accelerator communication methods are used, then data movement overhead is reduced, but out-of-order execution is restricted and task control is limited
Solution Approach 1:
The patent merges the accelerator invocation mechanism with the CPU's existing out-of-order execution infrastructure. Accelerator tasks are integrated into the instruction stream and processed by the same reorder buffer, reservation stations, and execution units that handle regular CPU instructions, enabling seamless out-of-order execution without requiring separate control mechanisms.
Solution Approach 2:
The patent makes the CPU core's execution infrastructure universal by enabling it to handle both regular CPU instructions and accelerator invocation instructions through the same pipeline stages. The reorder buffer, reservation stations, and execution units are designed to process mixed instruction types uniformly, eliminating the need for separate handling paths.
2Productivity
If sequential programming model is used, then control overhead is reduced, but parallelism is limited and scalability is hindered
Solution Approach 1:
The patent introduces dynamic parallelism by allowing accelerator tasks to be issued speculatively and out-of-order based on runtime conditions. The system dynamically determines execution order and timing rather than following a fixed sequential pattern, enabling the CPU to exploit parallelism opportunities as they arise during execution.
Solution Approach 2:
The patent enables speculative execution of accelerator tasks before their results are needed by subsequent instructions. The reorder buffer holds speculative accelerator invocations and resolves dependencies later, allowing the system to begin accelerator work in advance rather than waiting for sequential completion.
3Productivity
If accelerator tasks are executed in-order, then control simplicity is maintained, but execution efficiency and parallelism are reduced
Solution Approach 1:
The patent enables accelerator tasks to self-manage their execution timing and ordering through the CPU's existing out-of-order infrastructure. Each accelerator invocation instruction automatically interacts with the reorder buffer, reservation stations, and execution units to determine its optimal execution time, eliminating the need for explicit ordering control by software.
4Productivity
If speculative execution is disabled, then control overhead is reduced, but performance and parallelism are limited
Solution Approach 1:
The patent implements feedback mechanisms through the reorder buffer and dependency tracking infrastructure that monitor execution progress and resolve speculative decisions. When speculative accelerator tasks are issued, the system tracks their dependencies and outcomes, using this feedback to determine commit order and handle mispredictions, enabling performance gains without requiring complex external control.
Data Source
AI summary
Techniques for speculative invocation of accelerators in out-of-order pipelines are described. In some examples, a processor core at least comprising: decoder circuitry to at least decode an accelerator task instruction, scheduling circuitry to at least schedule the decoded accelerator task instruction to execute on an accelerator, a port coupled to the accelerator, and at least one register to store a result of the decoded accelerator task instruction; is coupled to the accelerator to execute the decoded accelerator task instruction and provide the result to the processor core through the port coupled to the accelerator.