SIMD Execution Unit Channel Homogeneity Detection
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Solution Overview
Problem
Graphics processing units (GPUs) with narrower SIMD widths face inefficiencies in area usage due to repeated controllers for wider SIMDs, leading to power savings but reduced area efficiency, especially when processing similar data types like pixel data.
Innovation Solution
Implementing a mechanism that determines when all channels have the same values, allowing execution and writing to be limited to a single channel, utilizing a scoreboard to efficiently process SIMD instructions and reduce redundant operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If narrower physical SIMD channels are used to execute instructions, then power consumption is reduced due to suppressed data toggles, but area efficiency deteriorates due to repeated controllers for each wide SIMD
Solution Approach 1:
The patent merges multiple narrow physical SIMD channels into a single wide logical SIMD channel by combining their controllers. This allows the system to maintain the power efficiency of narrow channels while achieving the area efficiency of a wide channel by sharing control resources across multiple data processing lanes.
Solution Approach 2:
The controller is designed to be universal, serving multiple functions by managing both narrow physical channels and wide logical channels. This multi-functional controller can dynamically allocate resources to handle different SIMD widths, making the same hardware structure adaptable to various processing requirements without duplication.
2Area of stationary object
If controllers are repeated for each wide SIMD to maintain area efficiency, then area usage improves, but power consumption increases due to additional control logic
Solution Approach 1:
Multiple controllers that would traditionally be duplicated for each wide SIMD are merged into a single shared controller. This consolidation reduces the total control logic area and power consumption while maintaining the ability to process wide SIMD instructions through coordinated control of multiple narrow physical channels.
Solution Approach 2:
Instead of copying controllers for each wide SIMD, the patent uses a single controller that manages multiple narrow channels. The control signals are effectively copied or distributed to the appropriate narrow channels, achieving wide SIMD functionality without the overhead of multiple full controllers.
3Reliability
If all channels are executed and written to when processing SIMD instructions, then completeness of data processing is ensured, but resource efficiency deteriorates due to redundant operations on identical data
Solution Approach 1:
The patent implements partial action by allowing the execution unit to process only a subset of channels when data values are identical across channels. The scoreboard tracks which channels have been processed, enabling the system to perform fewer redundant operations while maintaining data correctness through selective channel execution and writing.
Solution Approach 2:
The scoreboard mechanism provides feedback about the state of data values across channels. This feedback allows the execution unit to make informed decisions about which channels need processing, avoiding redundant operations on channels with identical data values while ensuring that all necessary channels are eventually processed for correctness.
Data Source
AI summary
A processing apparatus is described. The apparatus includes a graphics processing unit (GPU), including a register file having a plurality of channels to store data and an execution unit to examine data at each of the plurality of channels, read a data value from a first of the plurality of channels upon a determination that each of the plurality of channels has the same data and execute a single input multi data (SIMD) instruction based on the data value.