In-Place Matrix Transpose via Diagonal Tile Scheduling

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Solution Overview

Problem

In-place matrix transpose operations face challenges in performing memory accesses in parallel due to memory-bound nature and inefficiencies in existing indexing schemes, leading to serialized memory access and high memory overhead in out-place operations.

Innovation Solution

The system partitions the matrix into tiles and schedules operations using a staggered diagonal ordering scheme, allowing parallel memory access by traversing diagonals through the matrix, maximizing data access in parallel and avoiding memory channel conflicts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If out-place transpose operation is used, then memory access simplicity is improved, but memory overhead increases and memory capacity is limited

Engineering Contradiction:
Improvememory access simplicityVSAvoidmemory overhead
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The matrix is divided into multiple tiles, where each tile can be transposed independently. This segmentation allows the transpose operation to be performed in-place by processing smaller units, reducing the overall memory overhead while maintaining operational simplicity through systematic tile-by-tile processing.

Inventive Principle:
Principle #1Segmentation

2Quantity of substance

If in-place transpose operation is used, then memory overhead is reduced, but parallel memory access becomes challenging

Engineering Contradiction:
Improvememory overheadVSAvoidparallel memory access efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

By dividing the matrix into tiles, the system can process multiple tiles in parallel across different memory channels. Each tile's transpose operation is independent, enabling parallel execution while maintaining in-place memory usage, thus resolving the contradiction between reduced memory overhead and parallel access efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to the indexing scheme by using staggered diagonal ordering instead of traditional row-major or column-major ordering. This dimensional change in indexing allows elements that need to be accessed in parallel to be distributed across different memory channels, enabling parallel memory access in in-place transpose operations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If traditional indexing scheme is used, then implementation simplicity is improved, but memory channel conflicts increase and parallel access efficiency decreases

Engineering Contradiction:
Improveimplementation simplicityVSAvoidparallel access efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent transforms the traditional two-dimensional row-major or column-major indexing into a staggered diagonal indexing scheme. This dimensional transformation reorganizes the access pattern so that elements accessed in parallel operations are distributed across different memory channels, eliminating conflicts while maintaining implementation feasibility through systematic index calculation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10067911B2High performance inplace transpose operations
Publication Date: 2018.09.04 ADVANCED MICRO DEVICES INC
  • US10067911B2 patent drawing
  • US10067911B2 patent drawing
  • US10067911B2 patent drawing

AI summary

Systems, apparatuses, and methods for performing in-place matrix transpose operations are disclosed. Operations for transposing tiles of a matrix are scheduled in an order determined by moving diagonally through tiles of the matrix. When a diagonal line hits a boundary, then a tile on a new diagonal line of the matrix is selected and operations are scheduled for transposing this tile. Only tiles within a triangular region of the matrix are scheduled for being transposed. This allows memory access operations to be performed in parallel, expediting the matrix transpose operation compared to linear tile indexing.