Mojo struct
Signal
@register_passable(trivial)
struct Signal
A synchronization primitive for coordinating GPU thread blocks across multiple devices.
This struct provides counter-based synchronization between thread blocks on different GPUs. It maintains two sets of counters:
- self_counter: Used by blocks on the current GPU to signal their progress
- peer_counter: Used to track progress of blocks on other GPUs
Note: The counters use unsigned integers that may overflow, but this is safe since unsigned integer overflow has well-defined behavior.
Fields
- self_counter (
StaticTuple[StaticTuple[SIMD[uint32, 1], 8], 512]): A 2D array of counters with shape (MAX_NUM_BLOCKS_UPPER_BOUND, MAX_GPUS). Each counter tracks the progress of a specific thread block on the current GPU. Thread blocks increment their corresponding counter to signal completion of a phase, allowing other GPUs to detect when synchronization points are reached. The counters use atomic operations to ensure proper synchronization across devices. - peer_counter (
StaticTuple[StaticTuple[StaticTuple[SIMD[uint32, 1], 8], 512], 2]): A 3D array of counters with shape (2, MAX_NUM_BLOCKS_UPPER_BOUND, MAX_GPUS). Contains two sets of counters to handle two synchronization points safely. The dual counter design prevents race conditions where a peer block arrives at the second sync point before the current block passes the first sync point.
Implemented traits
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