pub const SIGN_LATENCY_CYCLES: f64 = 173.0;Expand description
Idle signing latency: native simulation (cycle-accurate RHDL, not the
card) of the slice signer behind the uBFT service’s request stream
(tests/ubft_signer.rs, 2 slices, 8 isolated requests after the first
certificate: 171–188 cycles, mean 173.1, every frame the reference
signature). A key is cached and its certificate made, so this is the
message digest, the 68-cycle schedule slot it waits for, the node reads
from the key cache, the 26-beat frame and the relay registers. It replaces
an unmeasured 64-cycle estimate (28 BLAKE3 + 26 beats + ~10 registers)
that left out the schedule wait and the cache reads. The batch kernel’s
HBM reader and writer add their own cycles (not measured).
Unit: clock cycles. The planner uses it for idle latency and, with Little’s law, for the number of signatures in flight.