About

A POC for SablierV2LockupTranched contract and a benchmark.

See here for more details.

Problem

The problem with SablierV2LockupDynamic is that it needs to have two segments for one unlock, see how is the unlock in steps curve implemented here.

For SablierV2LockupTranched, the above example, it would be implemented like this:

    uint256 trancheSize = 10;
    tranches = new Tranche[](trancheSize);

    uint128 unlockAmount = totalAmount / trancheSize;
    uint40 stepDuration = 10 days;

    for (uint256 i = 0; i < trancheSize; ++i) {
        tranches[i] = Tranche({ amount: unlockAmount, milestone: uint40(block.timestamp) + stepDuration });
        stepDuration += 10 days;
    }

Notice that the tranche size in this case is half, leading to fewer storage variables and less arrays traversed when calculating the withdrawable amount.

Benchmark

Note: the benchmark tests can be found here.

For the benchmarks, I have considered the following number of unlocks: 2, 4, 6, 12, 24, 36, 48, 60. These numbers are intended to reflect real-world scenarios (can be viewed as months).

If we were to compare the gas for the same length of segments/tranches, the difference would not be that big. However, as mentioned above, LockupTranched uses half the number of tranches for the same number of unlocks compared to LockupDynamic, so it is indeed more efficient.

Gas Improvements Per Unlock

Number of Unlocks	Improvement in createWithMilestone	Improvement in withdraw
2	51,247	14,508
4	101,482	15,453
6	151,725	16,400
12	302,502	19,242
24	604,561	24,950
36	907,599	30,689
48	1,210,982	36,460
60	1,515,272	42,261

Gas Improvements Per Segments/Tranches

Number of Segments/Tranches	Improvement in createWithMilestone	Improvement in withdraw
2	2,122	13,367
4	3,211	13,169
6	4,302	12,973
12	7,604	12,382
24	14,221	11,204
36	20,924	10,028
48	27,736	8,858
60	34,686	7,691

Full Tables

You can also run this command to generate the benchmark:

forge test -vv

LockupDynamic: createWithMilestone		LockupTranched: createWithMilestone
Segments Length	Gas	Tranches Length	Gas
2	182,675	2	180,553
4	231,800	4	228,589
6	280,932	6	276,630
8	330,071
12	428,355	12	420,751
24	723,253	24	709,032
36	1,018,316	36	997,392
48	1,313,593	48	1,285,857
60	1,609,134	60	1,574,448
72	1,904,991
96	2,496,839
120	3,089,720

Note: the withdrawable amount was calculated for the last segment/tranche.

LockupDynamic: withdraw		LockupTranched: withdraw
Segments Length	Gas	Tranches Length	Gas
2	27,669	2	14,302
4	28,810	4	15,641
6	29,952	6	16,979
8	31,094
12	33,379	12	20,997
24	40,239	24	29,035
36	47,107	36	37,079
48	53,985	48	45,127
60	60,872	60	53,181
72	67,768
96	81,587
120	95,442