Block Fullness with Operational and Normal Dispatches

[shawntabrizi]

In Substrate, we allow normal dispatches to only use up to a certain percent of a block's maximum weight. An operational dispatch on the other hand can use the full block weight.

As implemented currently, the following "equal" scenarios will not have the same result:

Max Block Weight: 1000, Available Block Ratio 75%

Scenario 1:

• Add normal dispatch with weight 750
• Add operational dispatch with weight 250
• Successful block is built with both dispatches

Scenario 2:

• Add operational dispatch with weight 250
• Add normal dispatch with weight 750
• Normal dispatch is rejected because it would push the block weight over 750.

This would be pretty simply solved by separating the tracking of operational and normal dispatches, but would ultimately alter the existing logic for Substrate.

This issue is to call out this issue, to agree on what behavior we want, and to make our documentation explicit about that behavior.

cc @thiolliere @kianenigma