VAT Reduction

[bw-solana]

As part of reducing slot times and shortening wall clock time of epochs, we can reduce the Validator Admission Ticket (VAT) fee.

I see a few ways we could write the SIMD:

1. Braindead change from 1.6 SOL --> 0.8 SOL t hat we activate after slot time reductions (which likely come before Alpenglow anyways)
2. Same as 1, but gate the reduction on 200ms slots feature gate being active as well. Protect from screwing up the feature order activation
3. New SIMD that tapers down 1.6, 1.4, 1.2, 1.0, 0.8 as we move slot times down from 400, 350, 300, 250, 200. Probably unnecessary given likely feature order is reduce slot times, reduce VAT, enable Alpenglow. But this would help in the case where Alpenglow gets enabled first
4. Amend SIMD-0525 to include this tapering from 3 with the existing feature activations
5. Something else?

[t-nelson]

four. always maximize optionality

i am getting concerned with how many simds we're approving that need amended tho. suggests that we are not in fact getting the correct eyes on changes and missing collateral damage. ag blast radius and unknowable deployment timeline also getting in the way

[7layermagik]

I don't think a VAT reduction before the slot times are reduced would lead to any realistic issues at all currently given how few validators there are at the moment... so 2, 3, and 4 seem unnecessary.

Longer term, a dynamic VAT that goes up as the validator set size upper limit is approached makes more sense than the current arbitrary static fee. A "smart" VAT would 1) offer better sybil protection 2) address ongoing arguments about voting fees that we have had for years now and 3) would also provide an additional source of burn in the happy case where Solana's economy is booming so much that the validator set is once again growing toward 2k validators (or whatever hard upper limit is set). This additional burn source goes beyond the recent burn per cu proposal because that proposal cannot extract additional burn once blocks are full cu wise (imagine blocks are full, but 10x total rewards vs another scenario where they are also full).

[bw-solana]

on the off chance that Alpenglow makes it in before slot time reductions, might as well make sure the VAT scales down as slot times are reduced.

I agree prematurely lowering VAT to 0.8 wouldn't be catastrophic, but it's also trivial to just lock this in with slot time.

Also agree there are more sophisticated mechanisms we can use to price the VAT. My preference is to not block getting this simple scaling factor in on doing something more exotic. The latter is likely to be a longer, more contentious debate.

[bw-solana]

Opened #556 to specify option 4