Benchmark extra macro

Question

What does the #[extra] macro do in benchmarks?

I was looking at how benchmarks are being implemented on the Balances pallet. I notice the following benchmarks:

benchmarks_instance_pallet {
  transfer {}

  #[extra]
  transfer_best_case {}

 ...
}

When I searched the code for T::WeightInfo::transfer_best_case() I could not find where that was used in the balances code.

Can you please explain what the macro extra is doing?

Also, when looking at the benchmarks for transfer extrinsic I was expecting some seeded account data to calculate the worst-case scenario. Can you please explain the decision on not seeded accounts before hand?

Answer 1

That's an undocumented tag allowing to skip some benchmarks unless --extra flag is given. It was introduced in this PR. From the description:

• A new #[extra] tag is introduced into the benchmarks! macro, allowing users to mark benchmarks as "extra" and have them excluded from the default running benchmarks.
• Added --extra feature flag to benchmarking-cli to enable users to run the extra benchmarks