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Mojo function

init_signal_buffer

def init_signal_buffer(signal_buffer: DeviceBuffer[DType.uint8], ctx: DeviceContext)

Initializes a freshly allocated signal buffer for any comm collective.

Mojo-side equivalent of Signals.buffers() in allreduce.py: zero-fills the whole buffer (the correct start state for the barrier counters and lamport_state), then overwrites the embedded Lamport region with the -0.0 sentinel so the barrier-free Lamport allreduce reads every pack as "not ready". Both memsets are enqueued on ctx's stream, so the sentinel fill is correctly ordered after the zero-fill.

Args:

signal_buffer (DeviceBuffer[DType.uint8]): This rank's signal buffer (at least sizeof(Signal) bytes).
ctx (DeviceContext): The device context for this rank's GPU.