Transaction Routing Arbitration Using Default Attribute Values
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Solution Overview
Problem
In integrated circuits, transaction routing devices face challenges in arbitration that affect signal timings, leading to slower performance or increased power consumption, particularly when multiple transactions contend for the same destination, as existing methods require buffering the entire transaction to capture actual attribute values, which is costly in terms of power and area.
Innovation Solution
Implementing an arbitration circuitry that uses a default attribute value for new candidate transactions in the first processing cycle, storing the actual attribute value for subsequent cycles, allowing timely arbitration and selection without the need for buffering the entire transaction, thus reducing power consumption and area requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clock frequency is reduced to meet arbitration timing requirements, then timing requirements are satisfied, but performance deteriorates
Solution Approach 1:
The patent segments the arbitration process into two distinct phases: a first arbitration phase that uses default attribute values for quick decision-making, and a second arbitration phase that uses actual attribute values for final selection. This segmentation allows the critical timing path to be shortened in the first phase, meeting timing requirements without reducing clock frequency, while still incorporating actual attribute values in the second phase to ensure correct arbitration outcomes.
Solution Approach 2:
The patent performs preliminary arbitration using default attribute values before the actual attribute values are ready. The arbitration circuitry conducts an initial arbitration pass with placeholder default values, allowing the critical timing path to be completed within the clock cycle. Subsequently, when actual attribute values become available, a second arbitration pass determines the final transaction selection, thus avoiding the need to slow down the clock for the complete arbitration process.
2Reliability
If the operating voltage is increased to meet arbitration timing requirements, then timing requirements are satisfied, but power consumption increases
Solution Approach 1:
The patent divides the arbitration into two stages: a first stage using default attribute values that completes within the clock cycle at normal voltage, and a second stage using actual attribute values for final selection. This segmentation eliminates the need to increase operating voltage to meet timing requirements, as the critical timing path is satisfied in the first stage without voltage escalation, thereby maintaining normal power consumption levels.
Solution Approach 2:
The patent performs a preliminary arbitration using default attribute values that can be completed at normal operating voltage within the clock cycle. This preliminary action satisfies the critical timing path without requiring voltage increase. The actual attribute values are then used in a subsequent arbitration pass, allowing correct arbitration decisions to be made without the power consumption penalty of elevated operating voltage.
3Measurement precision
If the entire transaction is buffered to capture actual attribute values, then arbitration accuracy is improved, but area and power consumption increase
Solution Approach 1:
The patent extracts only the essential attribute values from the complete transaction data for arbitration purposes. Instead of buffering entire transactions, the system captures and buffers only the relevant attribute fields (such as priority, destination, or other arbitration-critical parameters). This extraction approach maintains arbitration accuracy by preserving the decision-making information while dramatically reducing the buffering resources required in terms of area and power consumption.
Solution Approach 2:
The patent creates simplified copies of the transaction data that contain only the attribute values necessary for arbitration, rather than copying or buffering the entire transaction. These attribute-only copies are stored in compact buffers and used for arbitration decisions, achieving the required arbitration accuracy with minimal area and power overhead compared to buffering complete transactions.
4Measurement precision
If the entire transaction is buffered to capture actual attribute values, then arbitration accuracy is improved, but power consumption increases
Solution Approach 1:
The patent extracts only the essential attribute values from the complete transaction data for arbitration purposes. Instead of buffering entire transactions, the system captures and buffers only the relevant attribute fields (such as priority, destination, or other arbitration-critical parameters). This extraction approach maintains arbitration accuracy by preserving the decision-making information while dramatically reducing the buffering resources required in terms of area and power consumption.
Solution Approach 2:
The patent creates simplified copies of the transaction data that contain only the attribute values necessary for arbitration, rather than copying or buffering the entire transaction. These attribute-only copies are stored in compact buffers and used for arbitration decisions, achieving the required arbitration accuracy with minimal area and power overhead compared to buffering complete transactions.
Data Source
AI summary
A transaction routing device (e.g. an interconnect) for routing transactions in an integrated circuit includes arbitration circuitry for performing arbitration between a plurality of candidate transactions using attribute values associated with the candidate transactions. Candidate transactions are selected for routing to a destination device in dependence on the arbitration. In a cycle in which a new candidate transaction is received, the arbitration is performed using a default attribute value as the attribute value for the new transaction. Meanwhile, the actual attribute value is stored to an attribute storage unit. In a following processing cycle, if the new candidate transaction has not yet been selected for muting, then the arbitration is performed using the actual attribute value stored in the storage unit.