# Goal
The goal of this PR is to evaluate and minimize PoV consumption by
`stateful-storage` pallet.

Closes #1782 

# Discussion
- refactored benchmarks to calculate the max of time and PoV
- decreased `additional-trie-layers` number
- decreased `MaxItemizedPageSizeBytes ` from 64KiB to around 10KiB (will
allow around 292 of 32 bytes itemized public keys)

# Improvements
- by applying mentioned changes the PoV for `apply_item_actions` got
reduced from **45KB** to **15KB**
- by applying mentioned changes the PoV for `upsert` and `delete` pages
got reduced from **12KB** to **6KB**

# Future improvements
- by using PoV clawback we can further reduce the PoV sizes. A
[PR](paritytech/polkadot-sdk#1462) to track

# Checklist
- [x] Benchmarks added
- [x] Weights updated

---------

Co-authored-by: Frequency CI [bot] <do-not-reply@users.noreply.github.com>
Co-authored-by: Wil Wade <wil.wade@unfinished.com>

…lock Utilization (#43)

paritytech/polkadot-sdk#1462 has been open for a
while and is now well-reviewed. Opening an RFC since it introduces a new
host function that is relevant for parachains and light-clients.

This PR provides the infrastructure for the pov-reclaim mechanism
discussed in paritytech#209. The goal is to provide the current proof size to the
runtime so it can be used to reclaim storage weight.

## New Host Function
- A new host function is provided
[here](https://github.com/skunert/polkadot-sdk/blob/5b317fda3be205f4136f10d4490387ccd4f9765d/cumulus/primitives/pov-reclaim/src/lib.rs#L23).
It returns the size of the current proof size to the runtime. If
recording is not enabled, it returns 0.

## Implementation Overview
- Implement option to enable proof recording during import in the
client. This is currently enabled for `polkadot-parachain`,
`parachain-template` and the cumulus test node.
- Make the proof recorder ready for no-std. It was previously only
enabled for std environments, but we need to record the proof size in
`validate_block` too.
- Provide a recorder implementation that only the records the size of
incoming nodes and does not store the nodes itself.
- Fix benchmarks that were broken by async backing changes
- Provide new externalities extension that is registered by default if
proof recording is enabled.
- I think we should discuss the naming, pov-reclaim was more intuitive
to me, but we could also go with clawback like in the issue.

## Impact of proof recording during import
With proof recording: 6.3058 Kelem/s
Without proof recording: 6.3427 Kelem/s

The measured impact on the importing performance is quite low on my
machine using the block import benchmark. With proof recording I am
seeing a performance hit of 0.585%.

---------

Co-authored-by: command-bot <>
Co-authored-by: Davide Galassi <davxy@datawok.net>
Co-authored-by: Bastian Köcher <git@kchr.de>

# Goal
The goal of this PR is to evaluate and minimize PoV consumption by
`stateful-storage` pallet.

Closes #1782 

# Discussion
- refactored benchmarks to calculate the max of time and PoV
- decreased `additional-trie-layers` number
- decreased `MaxItemizedPageSizeBytes ` from 64KiB to around 10KiB (will
allow around 292 of 32 bytes itemized public keys)

# Improvements
- by applying mentioned changes the PoV for `apply_item_actions` got
reduced from **45KB** to **15KB**
- by applying mentioned changes the PoV for `upsert` and `delete` pages
got reduced from **12KB** to **6KB**

# Future improvements
- by using PoV clawback we can further reduce the PoV sizes. A
[PR](paritytech/polkadot-sdk#1462) to track

# Checklist
- [x] Benchmarks added
- [x] Weights updated

---------

Co-authored-by: Frequency CI [bot] <do-not-reply@users.noreply.github.com>
Co-authored-by: Wil Wade <wil.wade@unfinished.com>