Cost model for Reddit Bakeoff on Arbitrum

	A	B	C	D	E	F	G
1	brown cells are parameters you can adjust		green cells are from measurement of Reddit's contracts running on Arbitrum
2
3	workload factor	1	times Reddit's nominal workload
4	fraction of users who claim tokens	20%
5				in batches	in batches
6	MIX OF OPERATIONS	ops per day	batch size	avg L1 gas per op	avg L2 ArbGas per op	number of records at L2 (assuming system remembers 1 year of ops)
7	mass minting	20,000	5000	340	64,379	14,610,000	<--- number of accounts assumed
8	claim	4,000	14	7,010	720,061	2,922,000
9	subscription	5,000	17	4,901	282,719	3,650,000
10	burn	15,000	52	3,350	151,159	0
11	transfer	20,000	69	3,255	105,322	0
12	nominal operations per day	60,000
13
14	number of invited Arbitrum validators	8
15	value of chain, per account	$1
16	interest rate (annual)	6%
17	Ethereum gas price	$ 0.000012
18
19	computation cost per CPU-second	$0.00003	(based on Amazon EC2 t3a.xlarge default config)
20	storage cost per GB-day	$0.01	(based on Amazon EBS default config)
21
22	COMPARING APPROACHES	mass minting approach		claim-only approach
23	L1 gas / day	146,655,000		167,895,000
24	L2 ArbGas / day	7,075,000,000		8,667,664,000
25
26	VALIDATOR-INDEPENDENT COST / DAY
27	L1 gas	$1,759.86		$2,014.74
28	active validator capital lockup	$4.80		$4.80
29
30	PER-VALIDATOR COST / DAY
31	computation	$0.002		$0.002
32	storage	$0.009		$0.003
33
34	Total system-wide cost / day	$1,764.75		$2,019.55
35	Total system-wide cost / nominal operation	$0.029		$0.034
36
37	RESOURCE UTILIZATION
38	fraction of total worldwide L1 gas used	0.23%		0.26%
39	fraction of Reddit L2 Arbitrum chain capacity used	0.08%		0.10%
40
41	NOTES AND ASSUMPTIONS
42	Reddit's contracts were modified to add mass minting functionality (otherwise completely unmodified)
43	minting can be done in batches of 5000 operations
44	other ops grouped by optional aggregator into 1 batch per 5 minutes
45	cost "in batches" is total cost, divided by total number of ops; includes (amortized) per-batch costs
46	assume conservatively that 56 bytes of memory used per funded account and per subscription
47	"value of the chain, per account" is how much users value their L2 points, averaged over all users
48	number of accounts the system must track = number of mint events in one year
49	ArbGas measures L2 computation cost; single-CPU validator can do at least 100 Million ArbGas per second
50	"nominal operations" includes an operation for each token granted, but not for claims
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