ProveCommit and ProveReplicaUpdates in the way we charge gas activation costs (ProveReplicaUpdates pays those costs, ProveCommit does not).
If we want to re-balance gas costs we can either
- Subsidize Activation costs for ProveReplicaUpdates ⇒ ProveReplicaUpdates Avg. gas cost reduced by ~60%
or
- Make ProveCommit pay for activation gas costs ⇒ ProveCommit Avg. gas cost ~3x higherIf we want to re-balance gas costs we can:
- Either: Subsidize Activation costs for
ProveReplicaUpdates⇒ProveReplicaUpdatesAvg. gas cost reduced by 60% - Or: Make
ProveCommitpay for activation gas costs ⇒ProveCommitAvg. gas cost 3x higher. (scheduled for nv21)
Motivation
Gas costs given by deal activation are subsidized by Cron ProveCommit message (single precommited sectors), while are paid by ProveReplicaUpdates message when snapping and by ProveCommitAggregate for batched provecommit.
This asymmetry is already underlined in Separating proof validation from sector activation.
We want here to estimate which is the difference in gas unit (and thus cost) in both scenarios.
Gas Mismatch Estimation
We operate as follows
- Consider different blocks with different
ProveReplicaUpdatesby different SPs - Integrating the data with the average gas used values taken from FilFox.
What we'll have in the end will be the unit of gas needed for deal activation which will give us an estimation of what would be the overhead for deal activation in ProveCommit messages
Blocks considered
We consider two different blocks with ProveReplicaUpdates from which we'll extrapolate all the subcalls needed for deal activation and sector (re)activation which are subsidizez by cron in case of PreCommit messages.
Epoch 2843500
Epoch 2844239
Assumptions
- Cost of a unit of gas: 0.5 nanofil (5*10^{-10} FIL)
- It is an average value evaluated using the average gas fee and the average gas used of
ProveCommitandProveReplicaUpdatesfrom FilFox on May 9th, 2023 (that is, considering Avg. Gas Fee/Avg. Gas Used in both cases) - Average gas used for
ProveCommitSector~ 72M gas units - Average gas used for `ProveReplicaUpdates ~272.9M gas units
Subcalls of ProveReplicaUpdates to be considered
Deal Activation
- ActivateDeals
- ClaimAllocations (verified deals only)
- BurnExported (subcall of ClaimAllocations)
- VerifyDealsforActivation
- This call can be optimised out by using the information returned from Activate Deals
- https://github.com/filecoin-project/builtin-actors/blob/7140df519fa355f966aac2d7d6f6b014b5851154/actors/miner/src/lib.rs#L4968 (Activate Deals) https://github.com/filecoin-project/builtin-actors/blob/7140df519fa355f966aac2d7d6f6b014b5851154/actors/market/src/types.rs#L106-L118
- While VerifyDealsForActivation returns only Data CIDs: https://github.com/filecoin-project/builtin-actors/blob/7140df519fa355f966aac2d7d6f6b014b5851154/actors/market/src/types.rs#L88-L97
Sector Re-activation
- ThisEpochReward
- CurrentTotalPower
- UpdatePledgeTotal
- UpdateClaimedPower
Subcalls of ProveCommitAggregate to be considered
Deal Activation
- ActivateDeals
- ClaimAllocations
- BurnExported (subcall of ClaimAllocations)
- VerifyDealsforActivation
Sector Activation
- ThisEpochReward
- CurrentTotalPower
- UpdatePledgeTotal
- UpdateClaimedPower
- UpdateClaimedPower for new sectors is called once during the first WindowPoSt after the sector is on-boarded. It will also be called only once for all new sectors in the given deadline.
ProveReplicaUpdates
ActivateDeals | # deals | ClaimAllocations | BurnExported | VerifyDealsforActivation | ThisEpochReward | CurrentTotalPower | UpdatePledgeTotal | UpdateClaimedPower | |
Epoch 2843500 | 50M
| 1 | 64.7M | 14M | 4.5M | 1M | 1M | 5.2M | 24M |
55M | 1 | 69.6M | 14M | 4.5M | 1M | 1M | 5.2M | 24M | |
Epoch 2844239 | 72.7M | 2 | 93.2M | 14M | 4.5 | 1M | 1M | 5.1M | 23.6M |
72.1 | 2 | 99.3M | 14M | 4.5M | 1M | 1M | 5.1M | 23.6M | |
72.7 | 2 | 93.2M | 14M | 4.5M | 1M | 1M | 5.1M | 23.6M | |
423.5M | 16 | 423.2M | 14M | 20M | 1M | 1M | 5.1M | 23.5M |
- Amortized per Deal Activation gas cost ~ 100M gas unit
- Single Deal sector Deal Activation gas cost ~ 140.65M gas units
- Sector Re-Activation gas cost ~31.2M gas units
ProveCommitAggregate
ActivateDeals | ClaimAllocations | VerifyDealsforActivation | ThisEpochReward | CurrentTotalPower | UpdatePledgeTotal | UpdateClaimedPower | |
Epoch 2843500 | — | — | — | — | — | — | — |
Epoch 2844239 | ~56M per deal | ~62M per deal | — | 1M | 1M | 5.1M | — |
- Per Deal Activation gas cost ~ 118M gas units
- Sector Activation gas cost ~ 7.1 M gas units
Estimations
We consider the case of ProveReplicaUpdates with 1 deal per sector (since it is the case we are modeling in [2023Q2] CC Sector Upgrade: Guidelines and Modeling ).
Activation Estimates
Per-Deal Activation for ProveReplicaUpdates | Per-Deal Activation for ProveCommitAggregate | Sector Re-Activation ( ProveReplicaUpdates) | Sector Activation ( ProveCommitAggregate) | |
Estimation | 140.65M | 118M | 31.2M | 7.1M |
ProveCommit and ProveReplicaUpdates Gas Costs Comparison
ProveCommit | ProveReplicaUpdate | |
Average gas units | 71.8M | 272.9M |
Gas units w/o counting Activation | 71.8M | 101.05M
(272.9-140.65-31.2) |
Gas units counting Activation | 196.9
(71.8+118+7.1) | 272.9 |
Average cost assuming 0.5 nanofil per unit of gas w/o counting for Activation | 0.039 FIL
(currently paid) | 0.0505 FIL |
Average cost assuming 0.5 nanofil per unit of gas counting for Activation | 0.09845 FIL | 0.1268 FIL
(currently paid) |
Considering the average value for gas used by ProveReplicaUpdates ~ 273M, we have that activation gas costs (deal activation + sector activation) represent the ~ 62.9% of the gas fees.
Considering the average value for gas used by ProveCommit ~71.8M, we have that charging activation gas fees (deal activation + sector activation) to ProveCommit would increase its cost by 3x.