start_call

Call v257 → v277, v290 → current #92

Starts subnet operations/emissions .

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Call Workflow

start_call

1. Validation

Signature, nonce, mortality, fees

Signature

Nonce

Mortality

Fee payment

2. Pre-dispatch

Permission & state checks

Permission checks

State validation

3. Dispatch

Execute logic, modify state

FirstEmissionBlockNumberSet StartCallDelaySet FirstEmissionBlockNumber

4. Post-dispatch

Final result & fee settlement

ExtrinsicSuccess

Fees settled

Svelte Flow

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Used by: subnet ownersdevelopers

The Big Picture

Creating a subnet doesn't automatically start it. start_call is the 'go live' button - it activates emissions and marks the subnet as operational. This separation allows owners to configure parameters, attract initial miners, and test before going live with real incentives.

Why This Matters

Starting a subnet with no miners is wasteful - emissions have nowhere to go. The delayed start lets you set up properly. Advertise your subnet, onboard initial participants, configure parameters, then call start_call when ready.

Example Scenario

You created subnet 47 and spent a week onboarding 50 miners and 5 validators. Parameters are set, everything is tested. Call start_call(netuid=47). FirstEmissionBlockNumber is set to the current block. From now on, your subnet receives emissions and participants can earn.

Common Questions

What if I start too early?: Emissions go to whoever is registered. With few miners, they get concentrated rewards. With no miners, emissions might be wasted. Start when you have enough participation.
Can I pause after starting?: Not typically - start_call is a one-way activation. Once started, the subnet runs until dissolution. Plan your launch timing carefully.
Do I have to start manually?: For owned subnets, usually yes. Some subnet types might auto-start after conditions are met. Check your subnet's configuration.

Use Cases

Activate a newly created subnet after setup is complete
Begin emissions after configuration and testing
Launch subnet operations after gathering initial participants
Signal subnet readiness to the network

From Chain Metadata

Initiates a call on a subnet.

Input Parameters

#	Name	Type	Description
0	netuid	u16 NetUid	netuid: Subnet ID (u16, 0-65535)

Permissions

Origin

Unknown

Required Role

Any

Permission data inferred from metadata. May be incomplete.

Requirements

Subnet exists
Start conditions met (minimum neurons, configuration complete)
Caller is subnet owner or admin

Effects

Events Emitted

FirstEmissionBlockNumberSet StartCallDelaySet

Storage Modified

FirstEmissionBlockNumber

Postconditions

FirstEmissionBlockNumber set
Subnet begins receiving emissions
Subnet becomes active in network

Side Effects

Activates subnet in emission distribution
Miners and validators can start earning

Code Examples

import { createClient, Binary } from "polkadot-api";
import { getWsProvider } from "polkadot-api/ws";
import { sub } from "@polkadot-api/descriptors"; // generated by: npx papi add sub -w wss://entrypoint-finney.opentensor.ai:443

const client = createClient(getWsProvider("wss://entrypoint-finney.opentensor.ai:443"));
const api = client.getTypedApi(sub);

// Build start_call call (typed, named args)
const netuid = 1;

const tx = api.tx.SubtensorModule.start_call({
  netuid,
});

Version History

Version:

v257 block 5,228,683 1 args

v290 block 5,947,548 1 args Current

Runtime Info

View Source

Pallet Index: 7
Call Index: 92
First Version: v257
Current Version: v411

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