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SUBMIT A PRSUBMIT AN ISSUElast edit: May 17, 2024

Subnet Hyperparameters

This document presents the description of the allowed subnet hyperparameters. For any subnet, you can see the subnet hyperparameters by running this below command and selecting the netuid (i.e., selecting the subnet):

btcli subnet hyperparameters
Current hyperparameters list

Not all the hyperparameters in the output of btcli subnet hyperparameters are editable. See this line of code for the editable hyperparameters.

Setting the hyperparameters

Use the below command to set these hyperparameters:

btcli sudo set

serving_rate_limit

Description : Determines how often you can change your node's IP address on the blockchain. Expressed in number of blocks. Applies to both subnet validator and subnet miner nodes. Used when you move your node to a new machine.

Value : Usually this is set to 100 blocks.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.


min_difficulty, max_difficulty

Description : For subnets that have enabled PoW registration using network_pow_registration_allowed, these parameters determine the minimum and maximum difficulty for the Proof of Work calculation, respectively, expressed in terahashes. The actual difficulty is dynamic, auto-adjusting based on the number of registrations per adjustment interval. When a new adjustment interval is reached and the number of registrations or registration attempts in the previous adjustment interval exceeds the target number of registrations value, the difficulty will double in the following adjustment interval. If the number of registrations or registration attempts was fewer than the target number of registrations value, the difficulty will halve.

Setting : This parameter can be changed by the subnet owner.


weights_version

Description : Indicates the required minimum version of the subnet validator code.

Value : Set to 2013 for Subnet-1. : This means that every subnet validator in Subnet-1 must have at least version 2013 of the subnet validator code.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet. Setting this parameter to a version ensures that all the subnet validators use the same version of the code.


weights_rate_limit

Description : How often a subnet validator can set weights on the blockchain, expressed in number of blocks.

Value : Set to 100 for Subnet-1. : This means that after a subnet validator in Subnet-1 sends the weights to the blockchain, this subnet validator must wait for at least 100 blocks before sending the weights again to the blockchain.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.


max_weight_limit

This is the maximum weight that can be set by a subnet validator for a subnet miner, expressed as a value between 0 and 65535. This is a u16 (unsigned integer) type.

Value : Set to 455 for Subnet-1.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.

Example

Consider Subnet-1 where max_weight_limit is set to 455 and min_allowed_weights is set to 8. This means that each subnet validator must set weights for at least 8 subnet miners, and each such weight must not exceed 455.


immunity_period

Description : The immunity period is expressed in number of blocks. The immunity period is the number of blocks given to a subnet miner or a subnet validator at a UID before they are considered available for deregistration.

Value : Set to 7200 blocks for Subnet-1. The immunity_period at a UID starts when a subnet validator or a subnet miner is registered into the subnet.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.

A subnet miner or a subnet validator at a UID can perform poorly during the immunity_period without risking deregistration. If the UID still does not perform well even after the expiry of the immunity_period, then the subnet miner or subnet validator at that UID can be removed from the subnet. They will be removed when a new entity, i.e., a subnet miner or a subnet validator, requests to join the subnet.

When a subnet miner or a subnet validator is deregistered, they are required to register again to be considered for the subnet.

immunity period for a subnet

Immunity period also exists for a subnet. See Immunity period for a subnet.

Example

Consider Subnet-1, that has its immunity_period set to 7200 blocks. The duration of a block is 12 seconds. Hence a subnet validator or a subnet miner at any UID in Subnet-1 has 24 hours (=7200 blocks) from the moment they have registered, before they will be considered for deregistration.

Managing node deregistration during major updates

The subnet owner may modify the immunity_period at any given time, as well as temporarily turn off [network_registration_allowed] to allow established nodes (miners and/or validators) to adjust to major codebase updates without being deregistered.


min_allowed_weights

Description : The minimum number of UIDs a subnet validator must set weights on, before the subnet validator is allowed to set weights on the blockhain.

Value : Set to 8 for Subnet-1. : This means that any subnet validator who is trying to set weights on the blockchain must set weights on a minimum of 8 subnet miners before this subnet validator is able to successfully set its weights on the blockchain.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.

The value of min_allowed_weights sets a lower bound for the consensus. A higher value of min_allowed_weights means that the subnet validators are forced to set weights for more subnet miners. This parameter is mainly for security reasons, to eliminate unreasonably low consensus amongst the subnet validators in the subnet.

Example

A subnet validator can be considered as poorly performing if they set weights on only five subnet miners, when the min_allowed_weights is set to 8. This might occur due to a variety of reasons, for example: Maybe the subnet validator does not have enough stake to query the subnet miners, or maybe the subnet validator is part of a cabal engaged in cheating the system.

In this case, none of the actual weight-setting extrinsics that the subnet validator sends to the chain will be accepted. Hence on the chain it will look like this subnet validator has not set any weights at all. The Yuma Consensus may conclude that this subnet validator is performing poorly and after the immunity_period expires, this subnet validator could be deregistered to make room for others waiting to be miners or validators.

Minimum 1000 TAO required to set weights

A validate function will blacklist set-weights transactions from keys with less than 1000 TAO. This is designed to reduce chain bloat and make it easier for validators and root network participants to set weights on the chain.


tempo

Description : A duration of a number of blocks. Several subnet events occur at the end of every tempo period. For example, Yuma Consensus runs for the subnet and emissions are transferred to the hotkeys (delegated or staked).

Value : Set to 99 blocks for Subnet-1. All other subnets are set to 360 blocks.

Setting : Must not be changed.


adjustment_alpha

Description

A factor that controls the subnet registrations adjustment interval. This hyperparameter is now set to 0.97, a change from an earlier value of 0. A larger adjustment alpha will smooth the registration burn and POW cost for newly registered subnets, thus reducing the thrashing seen for registration costs. This parameter functions as a balance between registration burn and POW cost.

For example: If the target registration was 2 and there was 1 burn registration in the interval, the registration cost halving would apply to POW. On the other hand, if there were 1 POW registration, it would decrease the registration burn costs by half. In this way the adjustment_alpha mechanism tries to balance out the registration burn and POW costs.

important

By default this change from 0 to 0.97 does not effect already registered subnets. However, to take advantage of the new value, we strongly recommend that existing subnet owners update this value by setting it through the CLI, by running the below command. The --value 17893341751498265066 corresponds to setting the adjustment_alpha to 0.97. See this line of code.

btcli sudo set --param adjustment_alpha --value 17893341751498265066 --netuid <NETUID>

Setting : Must not be changed.


adjustment_interval

Description : Expressed in number of blocks. This is the number of blocks after which the recycle register cost and the pow_register difficulty are recalculated.

If the number of actual registrations that occurred in the last adjustment_interval is higher than the target_regs_per_interval, then the blockchain will raise the recycle register cost, by increasing the min_burn value by a certain amount, in order to slow down the actual registrations and bring them back to target_regs_per_interval value.

Value : Set to 112 for Subnet-1. : The blockchain uses this parameter together with the target_regs_per_interval and the min_burn and max_burn parameters.

Setting : Must not be changed.

Example

The Subnet-1 has its target_regs_per_interval set to 2. Consider a scenario where, in a 112-block interval (adjustment_interval) this subnet had 6 registrations. This is higher than target_regs_per_interval. The blockchain will now raise the minimum cost to recycle register, by increasing the min_burn value by a certain amount, in order to slow down the actual registrations.


activity_cutoff

Description : Expressed in number of blocks. If a subnet validator has not set weights on the blockchain for activity_cutoff duration, then the Yuma Consensus will consider this subnet validator as offline, i.e., turned off. The weights of this subnet validator are considered too old to be useful. The weights of this subnet validator slowly lose their impact over time and eventually will no longer be considered for consensus calcuation.

This parameter is applicable to subnet validators only.

Value : Set to 5000 (blocks) for Subnet-1.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.


network_registration_allowed

Description : True or False. Indicates whether this subnet allows registrations.

Value : Set to True for Subnet-1.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.


network_pow_registration_allowed

Description : True or False. Indicates whether this subnet allows POW (proof of work) registrations.

Setting : This parameter can be changed by the subnet owner. The value of this parameter varies from subnet to subnet.


target_regs_per_interval

Description : The target number of registrations desired in a adjustment_interval period. Expressed as an integer number.

Maximum number of registrations

The maximum number of registrations that can occur in an adjustment_interval is (3 * target_regs_per_interval).

Value : Set to 1 for Subnet-1.

Setting : Must not be changed.


min_burn, max_burn

Description : Minimum and maximum cost to register on this subnet. Expressed in Rao (10-9 TAO).

Setting : This parameter is automatically updated by the blockchain.


max_regs_per_block

Description : Maximum allowed registrations in this subnet per block.

Value : Set to 1 for Subnet-1.

Setting : Must not be changed.


max_validators

Description : Determines the maximum number of subnet validators you can have in the subnet.

Value : Default value is 64.

Setting : Must not be changed.