feat: stdlib databus

[ledwards2225]

Introduces a stdlib::DataBus class to facilitate calldata/return_data reads/writes. The work also includes:

• Circuit checker functionality for checking the validity of databus read gates (simply checks whether the {idx, value} pair in the gate corresponds to data in the corresponding bus vector). Closes Integrate ecc ops and databus into check_circuit barretenberg#842
• Tests for the stdlib DataBus (including failure tests and demonstration of check circuit)
• Minor updates to the builder notion of DataBus; now an array of BusVectors to improve interface from stdlib

[AztecBot]

Benchmark results

Metrics with a significant change:

• tx_sequencer_processing_time_ms (5): 1,752 (-17%)
• tx_sequencer_processing_time_ms (8): 586 (-19%)

Detailed results

All benchmarks are run on txs on the Benchmarking contract on the repository. Each tx consists of a batch call to create_note and increment_balance, which guarantees that each tx has a private call, a nested private call, a public call, and a nested public call, as well as an emitted private note, an unencrypted log, and public storage read and write.

This benchmark source data is available in JSON format on S3 here.

Values are compared against data from master at commit f038b704 and shown if the difference exceeds 1%.

L2 block published to L1

Each column represents the number of txs on an L2 block published to L1.

Metric	8 txs	32 txs	64 txs
l1_rollup_calldata_size_in_bytes	676	676	676
l1_rollup_calldata_gas	6,424	6,412	6,424
l1_rollup_execution_gas	585,757	585,745	585,757
l2_block_processing_time_in_ms	1,284 (-3%)	4,708	8,909 (-4%)
note_successful_decrypting_time_in_ms	226 (-3%)	572 (+2%)	919 (-14%)
note_trial_decrypting_time_in_ms	28.5 (-13%)	80.1 (+10%)	37.2 (-49%)
l2_block_building_time_in_ms	11,544 (-2%)	41,699 (-3%)	81,505 (-3%)
l2_block_rollup_simulation_time_in_ms	11,511 (-2%)	41,588 (-3%)	81,287 (-3%)
l2_block_public_tx_process_time_in_ms	5,933 (-3%)	23,311 (-3%)	46,608 (-3%)

L2 chain processing

Each column represents the number of blocks on the L2 chain where each block has 16 txs.

Metric	5 blocks	10 blocks
node_history_sync_time_in_ms	14,529 (+2%)	27,878 (+2%)
note_history_successful_decrypting_time_in_ms	1,335 (+3%)	2,346 (-4%)
note_history_trial_decrypting_time_in_ms	63.3 (-8%)	101 (-4%)
node_database_size_in_bytes	18,636,880	35,057,744 (+1%)
pxe_database_size_in_bytes	29,859	59,414

Circuits stats

Stats on running time and I/O sizes collected for every circuit run across all benchmarks.

Circuit	circuit_simulation_time_in_ms	circuit_input_size_in_bytes	circuit_output_size_in_bytes
private-kernel-init	178 (-1%)	44,377	26,164
private-kernel-ordering	160 (-1%)	50,830	39,026
base-parity	3,973	128	311
root-parity	1,061 (-2%)	1,244	311
base-rollup	13,944 (-2%)	110,464	861
root-rollup	49.0 (-2%)	4,359	725
private-kernel-inner	216	71,744	26,164
public-kernel-app-logic	119	47,695	40,661
public-kernel-tail	162 (-1%)	53,372	7,125
merge-rollup	9.25 (-16%)	2,568	861
public-kernel-teardown	117 (-18%)	47,695	40,661
public-kernel-setup	116 (-1%)	47,695	40,661

Tree insertion stats

The duration to insert a fixed batch of leaves into each tree type.

Metric	1 leaves	16 leaves	64 leaves	128 leaves	512 leaves	1024 leaves	2048 leaves	4096 leaves	32 leaves
batch_insert_into_append_only_tree_16_depth_ms	9.92 (-1%)	16.0 (-2%)	N/A	N/A	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_count	16.8	31.6	N/A	N/A	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_ms	0.577 (-2%)	0.495 (-2%)	N/A	N/A	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_32_depth_ms	N/A	N/A	45.4 (-3%)	71.0 (-2%)	223 (-4%)	447	844 (-3%)	1,677 (-3%)	N/A
batch_insert_into_append_only_tree_32_depth_hash_count	N/A	N/A	96.0	159	543	1,055	2,079	4,127	N/A
batch_insert_into_append_only_tree_32_depth_hash_ms	N/A	N/A	0.466 (-3%)	0.438 (-2%)	0.406 (-4%)	0.417	0.400 (-3%)	0.400 (-3%)	N/A
batch_insert_into_indexed_tree_20_depth_ms	N/A	N/A	53.7 (-3%)	104 (-3%)	327 (-4%)	664	1,270 (-3%)	2,534 (-3%)	N/A
batch_insert_into_indexed_tree_20_depth_hash_count	N/A	N/A	105	207	691	1,363	2,707	5,395	N/A
batch_insert_into_indexed_tree_20_depth_hash_ms	N/A	N/A	0.474 (-2%)	0.471 (-3%)	0.442 (-4%)	0.456	0.438 (-3%)	0.438 (-4%)	N/A
batch_insert_into_indexed_tree_40_depth_ms	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	60.5 (-2%)
batch_insert_into_indexed_tree_40_depth_hash_count	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	109
batch_insert_into_indexed_tree_40_depth_hash_ms	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	0.528 (-2%)

Miscellaneous

Transaction sizes based on how many contract classes are registered in the tx.

Metric	0 registered classes	1 registered classes
tx_size_in_bytes	40,372	496,534

Transaction size based on fee payment method

Metric	native fee payment method	fpc_public fee payment method	fpc_private fee payment method
tx_with_fee_size_in_bytes	905	1,161	1,377

Transaction processing duration by data writes.

Metric	0 new note hashes	1 new note hashes	2 new note hashes
tx_pxe_processing_time_ms	1,681 (-1%)	1,069	5,418

Metric	1 public data writes	2 public data writes	3 public data writes	4 public data writes	5 public data writes	8 public data writes
tx_sequencer_processing_time_ms	570 (-1%)	402	1,070	527 (+1%)	⚠️ 1,752 (-17%)	⚠️ 586 (-19%)

[ledwards2225]

Let's discuss this constant code path. I based the design of this class after the ROM table class which is why it's here. Originally thought it made sense but I'm not sure there's a valid reason to be able to extract databus entries without creating a gate.

[Rumata888]

Wouldn't the prover be able to replace the value in the witness, since there is nothing connecting the variable to databus column?

[Rumata888]

Everything looks good apart from the issue you've highlighted. Could you check that it doesn't create a soundness issue?