What does #[skip_meta] do?

Question

I notice some benchmarks in Frame have #[skip_meta].

What does this macro do?

Please explain when one should use this macro when benchmarking.

Answer 1

This is what I found.

https://github.dev/paritytech/substrate/blob/15cfd9c5dbbfa1f3ed49623eb55b67354d1645e9/frame/benchmarking/src/lib.rs#L1109-L1115

https://github.dev/paritytech/substrate/blob/15cfd9c5dbbfa1f3ed49623eb55b67354d1645e9/primitives/externalities/src/lib.rs#L306-L311

It would ignore the reads_and_writes if the benchmark was marked as #[skip_meta].

It won't calculate the reads_and_writes and won't put them into the BenchmarkResult.