Weight copying

Weight copying is a controversial topic in the Bittensor community. In this article, we look to explain weight copying and pros and cons of weight copying.

What is weight copying?

Validators weigh the work of each miner and create a ranked scoring - this is called setting weights. The weights are taken to the Yuma consensus to create the trust score for all of the validators.

Vtrust is the scoring of validators - and to score well in Vtrust, your weights must be similar to those of every other validator.

Weight copying is when a validator copies the consensus weights (or other validators' weights) instead of evaluating miners itself. This ensures a high Vtrust.

Why Weight copying?

When a validator uses the scoring from the Yuma consensus to place weights - they will score an extremely high Vtrust. High Vtrust leads to a higher percentage of emissions - which leads to higher revenue.

• On some subnets, miners will actively ignore requests from validators with low stake. To get a high stake, you need good results. It puts new validators in a chicken/egg situation. By weight copying, the validator is able to show good returns, and gain delegation.

Reasons to not weight copy

Validators that weight copy are not contributing to the Bittensor ecosystem. Validation of the miners is an essential part of the checks and balances of the Bittensor ecosystem. Weight copying does not give back into the ecosystem, and pushes the work onto a smaller group of validators.

Some subnets also block weight-copying validators from their data, forcing every validator to take part.

Responses to Weight copying: Commit Reveal

Commit Reveal is on by default on every subnet. Validators submit their weights timelock-encrypted, and the chain only decrypts and uses them commit_reveal_period tempos later (the subnet owner can change this period or turn Commit Reveal off). A weight copier only ever sees weights that are already stale, which costs it Vtrust and makes copying much less profitable. The Bittensor team have published a blog post and a technical whitepaper on commit reveal and its effect on weight copying.