refactor: note hashing gate optimizations

[benesjan]

Optimization of compute_note_hash_for_read_request function as proposed by Leila here

148160-87456=60704 gates saved

Since the function was called from multiple places in the transfer function the savings are larger for the whole token transfer:

1412919-1291447=121472 gates saved

Optimization of compute_siloed_note_hash:

We could do the same optimizations to compute_siloed_note_hash(...)

which resulted in additional drop of 60736 gates for the transfer function.

Overall drop of 173208 gates.

[benesjan]

• refactor: note hashes cleanup + optimization #7132
• refactor: note hashing gate optimizations #7130 👈
• master

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[benesjan]

Will address this one in follow-up PR.

[AztecBot]

Benchmark results

Metrics with a significant change:

• protocol_circuit_witness_generation_time_in_ms (private-kernel-inner): 1,033 (-18%)

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.

Proof generation

Each column represents the number of threads used in proof generation.

Metric	1 threads	4 threads	16 threads	32 threads	64 threads
proof_construction_time_sha256_30_ms	11,391	3,049	1,544 (+11%)	1,560 (-6%)	1,533 (+4%)
proof_construction_time_sha256_100_ms	44,687	12,029	5,641	5,581 (+1%)	5,529 (+1%)
proof_construction_time_poseidon_hash_ms	78.0	34.0	34.0 (-3%)	58.0	88.0 (+1%)
proof_construction_time_poseidon_hash_30_ms	1,518	417	202	224 (-1%)	262 (-1%)
proof_construction_time_poseidon_hash_100_ms	5,739	1,570 (-1%)	726	802 (+3%)	791 (-1%)

L2 block published to L1

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

Metric	4 txs	8 txs	16 txs
l1_rollup_calldata_size_in_bytes	1,412	1,412	1,412
l1_rollup_calldata_gas	9,452	9,466	9,464
l1_rollup_execution_gas	610,273	610,287	610,285
l2_block_processing_time_in_ms	792 (+7%)	1,403 (-1%)	2,668 (-1%)
l2_block_building_time_in_ms	25,350	50,905	99,617
l2_block_rollup_simulation_time_in_ms	25,249	50,605	99,259
l2_block_public_tx_process_time_in_ms	21,706	46,858	95,548

L2 chain processing

Each column represents the number of blocks on the L2 chain where each block has 8 txs.

Metric	3 blocks	5 blocks
node_history_sync_time_in_ms	6,940 (-1%)	9,732 (-2%)
node_database_size_in_bytes	12,169,296	16,138,320
pxe_database_size_in_bytes	16,254	26,813

Circuits stats

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

Circuit	simulation_time_in_ms	witness_generation_time_in_ms	proving_time_in_ms	input_size_in_bytes	output_size_in_bytes	proof_size_in_bytes	num_public_inputs	size_in_gates
private-kernel-init	129	503 (+2%)	12,215 (-1%)	20,634	67,190	92,352	2,819	524,288
private-kernel-inner	393	⚠️ 1,033 (-18%)	44,979 (+1%)	94,902	67,190	92,352	2,819	2,097,152
private-kernel-tail	370	1,874	46,517 (+2%)	99,121	71,733	14,912	399	2,097,152
base-parity	6.29	1,920 (-1%)	2,590	128	64.0	2,208	2.00	131,072
root-parity	49.4	47.3	34,193 (+1%)	27,100	64.0	2,720	18.0	2,097,152
base-rollup	7,903 (+1%)	4,370 (-1%)	72,724	170,330	756	3,648	47.0	4,194,304
root-rollup	112	63.9 (+1%)	19,671 (-1%)	25,309	620	3,456	41.0	1,048,576
public-kernel-setup	719 (-1%)	3,149 (+1%)	38,746	116,905	93,334	125,344	3,850	2,097,152
public-kernel-app-logic	612	4,193 (+3%)	39,823	116,905	93,334	125,344	3,850	2,097,152
public-kernel-tail	1,414	30,991 (-12%)	166,888 (+1%)	511,910	10,014	14,912	399	8,388,608
private-kernel-reset-small	592	2,263 (+9%)	40,849 (-2%)	123,313	67,190	92,352	2,819	2,097,152
public-kernel-teardown	620 (-1%)	4,190	40,422	116,905	93,334	125,344	3,850	2,097,152
merge-rollup	28.6 (-1%)	N/A	N/A	16,542	756	N/A	N/A	N/A
private-kernel-tail-to-public	N/A	7,216 (+1%)	84,837 (-1%)	N/A	N/A	125,344	3,850	4,194,304

Stats on running time collected for app circuits

Function	input_size_in_bytes	output_size_in_bytes	witness_generation_time_in_ms	proof_size_in_bytes	proving_time_in_ms	size_in_gates	num_public_inputs
ContractClassRegisterer:register	1,344	9,944	402	N/A	N/A	N/A	N/A
ContractInstanceDeployer:deploy	1,408	9,944	41.1 (+1%)	N/A	N/A	N/A	N/A
MultiCallEntrypoint:entrypoint	1,920	9,944	1,801	N/A	N/A	N/A	N/A
GasToken:deploy	1,376	9,944	983 (-1%)	N/A	N/A	N/A	N/A
SchnorrAccount:constructor	1,312	9,944	1,457	N/A	N/A	N/A	N/A
SchnorrAccount:entrypoint	2,304	9,944	2,833 (-1%)	16,768	51,270 (+1%)	2,097,152	457
Token:privately_mint_private_note	1,280	9,944	1,749 (+1%)	N/A	N/A	N/A	N/A
FPC:fee_entrypoint_public	1,344	9,944	383 (+2%)	16,768	10,414 (+2%)	524,288	457
Token:transfer	1,312	9,944	4,583 (-2%)	16,768	42,345 (-4%)	2,097,152	457
AuthRegistry:set_authorized (avm)	21,043	N/A	N/A	87,200	1,638 (+4%)	N/A	N/A
Token:transfer_public (avm)	44,971	N/A	N/A	87,865	4,062 (+1%)	N/A	N/A
AuthRegistry:consume (avm)	34,973	N/A	N/A	87,616	2,859 (-1%)	N/A	N/A
Benchmarking:create_note	1,344	9,944	1,397 (-1%)	N/A	N/A	N/A	N/A
SchnorrAccount:spend_private_authwit	1,280	9,944	73.4 (-3%)	N/A	N/A	N/A	N/A
Token:unshield	1,376	9,944	3,646 (-2%)	N/A	N/A	N/A	N/A
FPC:fee_entrypoint_private	1,376	9,944	4,614 (-1%)	N/A	N/A	N/A	N/A

AVM Simulation

Time to simulate various public functions in the AVM.

Function	time_ms	bytecode_size_in_bytes
GasToken:_increase_public_balance	67.8	13,873
GasToken:set_portal	16.8 (+2%)	3,495
Token:constructor	92.4 (-3%)	24,207
FPC:constructor	49.6 (-20%)	13,893
GasToken:mint_public	52.9	10,241
Token:mint_public	638 (-1%)	19,216
Token:assert_minter_and_mint	63.1 (+5%)	13,034
AuthRegistry:set_authorized	31.7	7,869
FPC:prepare_fee	150 (+1%)	15,187
Token:transfer_public	36.8 (+13%)	31,425
FPC:pay_refund	137 (+6%)	20,080
Benchmarking:increment_balance	2,678	15,465
Token:_increase_public_balance	56.1	15,089
FPC:pay_refund_with_shielded_rebate	144 (-1%)	21,167

Public DB Access

Time to access various public DBs.

Function	time_ms
get-nullifier-index	0.176

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	256 leaves	512 leaves	1024 leaves
batch_insert_into_append_only_tree_16_depth_ms	10.4	16.7 (-1%)	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_count	16.8	31.7	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_ms	0.600	0.513 (-1%)	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_32_depth_ms	N/A	N/A	48.4 (-1%)	75.5	131 (+1%)	244	467
batch_insert_into_append_only_tree_32_depth_hash_count	N/A	N/A	95.9	159	287	543	1,055
batch_insert_into_append_only_tree_32_depth_hash_ms	N/A	N/A	0.494 (-1%)	0.464	0.450 (+1%)	0.443	0.436
batch_insert_into_indexed_tree_20_depth_ms	N/A	N/A	59.7	113 (+2%)	181	354	689
batch_insert_into_indexed_tree_20_depth_hash_count	N/A	N/A	109	207	355	691	1,363
batch_insert_into_indexed_tree_20_depth_hash_ms	N/A	N/A	0.505	0.507 (+2%)	0.480	0.480 (+1%)	0.474
batch_insert_into_indexed_tree_40_depth_ms	N/A	N/A	72.6	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_count	N/A	N/A	133	N/A	N/A	N/A	N/A
batch_insert_into_indexed_tree_40_depth_hash_ms	N/A	N/A	0.518	N/A	N/A	N/A	N/A

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	85,672	670,983

Transaction size based on fee payment method

| Metric | |
| - | |

[sklppy88]

Crazy how seemingly inert things can cause so much of a gate count diff. Nice work !