Load Transfer Buffer Data Readiness Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In out-of-order processors, determining the last piece of data among data moving from one component to another can be challenging due to out-of-order data arrival, which complicates the execution of vector instructions like segmented loads or stores that require all data for proper execution.
Innovation Solution
Implementing a counter for each entry in the Load Transfer Buffer (LTB) or Store Transfer Buffer (STB) to track the number of expected writes, decrementing with each update, and awakening micro-operations when the counter reaches zero, ensuring data readiness for execution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If out-of-order execution is implemented to improve processor throughput, then productivity increases, but determining data readiness becomes more complex
Solution Approach 1:
The patent implements feedback mechanisms where completion status information flows back from execution units to the instruction dispatch mechanism. Counters and status bits provide continuous feedback about data readiness, enabling the system to dynamically adjust instruction issuance based on actual completion states rather than static ordering assumptions.
Solution Approach 2:
The patent introduces intermediary structures such as completion trackers, counters, and status registers that mediate between the out-of-order execution engine and the instruction stream. These intermediaries buffer and reconcile the timing differences between instruction issuance and data availability, decoupling the complexity of out-of-order execution from the simplicity of instruction ordering.
2Adaptability or versatility
If data is tracked in out-of-order fashion to maintain execution flexibility, then adaptability improves, but measurement precision of data readiness deteriorates
Solution Approach 1:
The patent segments the data readiness tracking into individual counter elements, one for each data element position. Each counter independently tracks the completion status of its corresponding data element, allowing precise measurement of exactly which elements are ready while maintaining flexibility in the overall execution order. This segmentation enables granular control over data readiness information.
Solution Approach 2:
The patent uses status bits and counter values as indicators that change state to reflect data readiness. Similar to color changes providing visual feedback, the counter values and status flags provide clear, unambiguous signals about whether data is ready, transforming the complex internal state into easily detectable readiness indicators that maintain measurement precision despite out-of-order execution.
Data Source
AI summary
A method for tracking of data readiness for load and store operations is disclosed. The method includes establishing a Load Transfer Buffer (LTB) entry, initializing a write counter configured to track a number or progress of write data that are expected to update the LTB entry, and tracking the number or progress of the write data that are expected to update the LTB entry. The tracking can include setting, in the write counter, the number of the write data that are expected to update the LTB entry, maintaining, until a next respective write data arrives to the LTB entry a current value corresponding to a respective number of write data left to update the LTB entry, and after receiving the next respective write data, adjusting the write counter to reflect a respective number of write data left to update the LTB entry.