Documentation / Concepts Bittensor / Subnets
Subnet Mechanisms
Dernière vérification le 2026-09-15
Each subnet can run multiple mechanisms (formerly called sub-subnets), allowing one subnet to work on several distinct challenges. This page covers how a subnet owner divides the subnet's alpha_out across those mechanisms.
For how alpha_out is then split among subnet owner / miners / validators inside a single mechanism, see Subnet emission overview. For the broader emission flow, see Subnet Emission: tao and alpha.
Mechanisms in a subnet
In V1 of subnet mechanisms, all miners and validators in a subnet compete in every mechanism. The owner sets how the subnet's per-block alpha_out is split across mechanisms via:
rust
pub fn sudo_set_mechanism_emission_split(
origin: OriginFor<T>,
netuid: NetUid,
maybe_split: Option<Vec<u16>>,
) -> DispatchResultThe maybe_split vector defines the percentage of subnet emission that flows to each mechanism.
A subnet may host up to 2 mechanisms. The subnet owner sets the count with sudo_set_mechanism_count; root can raise the network-wide limit (MaxMechanismCount) to a hard cap of 16.
How mechanism splits feed participant rewards
Inside each mechanism, the standard split applies (owner / miners / validators). Rewards for an individual miner or validator are calculated per mechanism and then aggregated to the subnet level using the mechanism-split weighting.
Concretely:
- A miner's
incentiveand a validator'sdividendare computed inside each mechanism. - Each mechanism contributes to the participant's subnet reward in proportion to its share of the split.
- The summed result is what the participant earns from the subnet per tempo.
See:
- Subnet emission overview — the canonical map of how
alpha_outis split inside a single mechanism. - Consensus for miners — how
incentiveis awarded inside a mechanism. - Dividends for Validators — how
dividendis awarded inside a mechanism.