Cost Estimator

The cost estimator is a convenient CLI tool to fetch the RISC-V instruction counts for generating ZKPs for a range of blocks for a given rollup.

The cost estimator requires fast network connectivity (500+ Mbps) because witness generation is bandwidth-intensive. Remote machines empirically perform better.

Overview

In the root directory, add the following RPCs to your .env file for your rollup:

Parameter	Description
`L1_RPC`	L1 Archive Node.
`L1_BEACON_RPC`	L1 Consensus (Beacon) Node.
`L2_RPC`	L2 Execution Node (`op-geth`).
`L2_NODE_RPC`	L2 Rollup Node (`op-node`).

More details on the RPC requirements can be found in the prerequisites section.

Running the Cost Estimator

You can run the cost estimator with unfinalized blocks as long as they're included in a batch posted to L1.

To run the cost estimator over a block range, run the following command:

RUST_LOG=info just cost-estimator <start_l2_block> <end_l2_block>

This command will split the block range into smaller ranges to model the workload run by op-succinct. It will then fetch the required data for generating the ZKP for each of these ranges, and execute the SP1 range program. Once each program finishes, it will collect the statistics and output the aggregate statistics.

Once the execution of the range is complete, the cost estimator will output the aggregate statistics and write them to a CSV file at execution-reports/{chain_id}/{start_block}-{end_block}.csv.

The execution of the cost estimator can be quite slow, especially for large block ranges. We recommend first running the cost estimator over a small block range to get a sense of how long it takes.

Useful Commands

cast block finalized -f number --rpc-url <L2_RPC>: Get the latest finalized block number on the L2.
cast bn --rpc-url <L2_RPC>: Get the latest block number on the L2.

Advanced Usage

There are a few optional flags that can be used with the cost estimator:

Flag	Description
`batch-size`	The number of blocks to execute in a single batch. For chains with higher throughput, you may want to decrease this value to avoid SP1 programs running out of memory. By default, the cost estimator will use a batch size of 300. For higher throughput chains, we've set the following defaults: Base (5), OP Mainnet (10), OP Sepolia (30).
`env-file`	The path to the environment file to use. (Ex. `.env.opmainnet`)
`use-cache`	Use cached witness generation. Use this if you're running the cost estimator multiple times for the same block range and want to avoid re-fetching the witness.

To run the cost estimator with a custom batch size, environment file, and using cached witness generation:

RUST_LOG=info cargo run --bin cost-estimator --release <start_l2_block> <end_l2_block> --env-file <path_to_env_file> --batch-size <batch_size> --use-cache

Sample Output

`stdout`

Executing blocks 5,484,100 to 5,484,200 on World Chain Mainnet:

Aggregate Execution Stats for Chain 480: 
 +--------------------------------+---------------------------+
| Metric                         | Value                     |
+--------------------------------+---------------------------+
| Batch Start                    |                 5,484,100 |
| Batch End                      |                 5,484,200 |
| Witness Generation (seconds)   |                        66 |
| Execution Duration (seconds)   |                       458 |
| Total Instruction Count        |            19,707,995,043 |
| Oracle Verify Cycles           |             1,566,560,795 |
| Derivation Cycles              |             2,427,683,234 |
| Block Execution Cycles         |            15,442,479,993 |
| Blob Verification Cycles       |               674,091,948 |
| Total SP1 Gas                  |            22,520,841,820 |
| Number of Blocks               |                       101 |
| Number of Transactions         |                     1,977 |
| Ethereum Gas Used              |               546,370,916 |
| Cycles per Block               |               195,128,663 |
| Cycles per Transaction         |                 9,968,636 |
| Transactions per Block         |                        19 |
| Gas Used per Block             |                 5,409,613 |
| Gas Used per Transaction       |                   276,363 |
| BN Pair Cycles                 |             7,874,860,533 |
| BN Add Cycles                  |               310,550,754 |
| BN Mul Cycles                  |             1,636,223,094 |
| KZG Eval Cycles                |                         0 |
| EC Recover Cycles              |                96,983,901 |
+--------------------------------+---------------------------+

csv

The CSV associated with the range will have the columns from the ExecutionStats struct. The aggregate data for executing each "batch" within the block range will be included in the CSV.

Here, the CSV is execution-reports/480/5484100-5484200.csv:

batch_start,batch_end,witness_generation_time_sec,total_execution_time_sec,total_instruction_count,oracle_verify_instruction_count,derivation_instruction_count,block_execution_instruction_count,blob_verification_instruction_count,total_sp1_gas,nb_blocks,nb_transactions,eth_gas_used,l1_fees,total_tx_fees,cycles_per_block,cycles_per_transaction,transactions_per_block,gas_used_per_block,gas_used_per_transaction,bn_pair_cycles,bn_add_cycles,bn_mul_cycles,kzg_eval_cycles,ec_recover_cycles
5484184,5484200,0,0,2877585481,299740342,462008456,2066943417,134844448,3304337522,17,316,81926057,540908658541982,596950839845253,169269734,9106283,18,4819179,259259,1017572318,40106182,211873811,0,11948870
5484100,5484120,0,0,3754402331,308914395,461086557,2932162167,134779302,4287957207,21,350,106933244,710095197624994,783053876268826,178781063,10726863,16,5092059,305523,1561122615,61455811,324588766,0,14705709
5484163,5484183,0,0,4005997705,311171459,435265918,3206173584,134844448,4570091686,21,365,110883055,690170871678571,779801718014140,190761795,10975336,17,5280145,303789,1676711949,66155955,346844998,0,17337504
5484121,5484141,0,0,4152572226,316652487,486166806,3293854188,134779302,4746305028,21,440,117222955,767310117504021,846733606470274,197741534,9437664,20,5582045,266415,1584230563,62520537,329178548,0,25124445
5484142,5484162,0,0,4917437300,330082112,583155497,3943346637,134844448,5612150377,21,506,129405605,935016666707488,1031433531465147,234163680,9718255,24,6162171,255742,2035223088,80312269,423736971,0,27867373

OP Succinct