Tile Synchronization Logic for Multi-Core Processor Latency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bulk synchronous parallel (BSP) processing in multi-tile processors faces challenges with load balancing, leading to reduced throughput due to differences in compute and exchange loads between tiles, which is exacerbated by physical separation, resulting in increased latency and uncertainty in synchronization across tiles.
Innovation Solution
A processing system with a dedicated machine code instruction for synchronizing specific groups of tiles, using hardwired logic in the interconnect to perform synchronization signaling via dedicated sync wires, allowing for flexible synchronization zones and reducing latency by keeping synchronization local to subsets of tiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barrier synchronization is implemented across all tiles in a multi-tile processor, then coordination between tiles is achieved, but latency increases due to physical separation and load balancing issues
Solution Approach 1:
The patent divides the tile array into multiple synchronization zones, where each zone independently performs barrier synchronization. This segmentation allows tiles within the same zone to synchronize locally without waiting for tiles in other zones, thereby reducing overall synchronization latency while maintaining coordination reliability within each zone.
Solution Approach 2:
The patent implements different synchronization behaviors for different spatial regions by creating distinct synchronization zones. Each zone can be optimized for its specific workload and physical location, allowing local synchronization to proceed faster than global synchronization would permit, thus reducing latency while maintaining necessary coordination.
2Measurement precision
If dedicated synchronization logic is implemented for each tile group, then synchronization precision is improved, but device complexity increases
Solution Approach 1:
The patent designs synchronization logic that can operate at multiple levels: within individual tiles, across groups of tiles, and potentially across the entire processor array. This multi-functional synchronization logic reduces the need for completely separate synchronization mechanisms for each tile group, thereby improving precision without proportionally increasing overall device complexity.
Solution Approach 2:
The patent implements a hierarchical synchronization structure where synchronization zones are nested within the overall tile array. Each synchronization zone contains its own barrier logic, which is nested within the larger processor architecture. This nesting allows precise local synchronization while reusing higher-level synchronization infrastructure, balancing precision requirements with complexity constraints.
Data Source
AI summary
A processing system comprising an arrangement of tiles and an interconnect between the tiles. The interconnect comprises synchronization logic for coordinating a barrier synchronization to be performed between a group of the tiles. The instruction set comprises a synchronization instruction taking an operand which selects one of a plurality of available modes each specifying a different membership of the group. Execution of the synchronization instruction cause a synchronization request to be transmitted from the respective tile to the synchronization logic, and instruction issue to be suspended on the respective tile pending a synchronization acknowledgement being received back from the synchronization logic. In response to receiving the synchronization request from all the tiles in the group as specified by the operand of the synchronization instruction, the synchronization logic returns the synchronization acknowledgment to the tiles in the specified group.