feat: change nullifier tree height to 20

[rahul-kothari]

Fix #2947.

Note - had to change the nullifier height to 20 instead of 32 since circuit tests use NullifierMemoryTreeTestingHarness which uses BB's Memory Tree which is limited to a max height of 20. I can't change it to 32 due to bad_alloc.

[AztecBot]

Benchmark results

Metrics with a significant change:

• circuit_simulation_time_in_ms (private-kernel-init): 47.4 (-47%)
• circuit_simulation_time_in_ms (private-kernel-ordering): 23.4 (-57%)
• circuit_simulation_time_in_ms (base-rollup): 862 (-61%)
• circuit_simulation_time_in_ms (root-rollup): 39.0 (-60%)
• circuit_simulation_time_in_ms (private-kernel-inner): 42.7 (-33%)
• node_history_sync_time_in_ms (5): 12,444 (-56%)
• node_history_sync_time_in_ms (10): 23,717 (-58%)
• note_history_successful_decrypting_time_in_ms (5): 2,550 (-66%)
• note_history_successful_decrypting_time_in_ms (10): 5,086 (-66%)
• l2_block_building_time_in_ms (8): 8,959 (-43%)
• l2_block_building_time_in_ms (32): 35,921 (-42%)
• l2_block_building_time_in_ms (128): 158,386 (-36%)
• l2_block_rollup_simulation_time_in_ms (8): 6,654 (-49%)
• l2_block_rollup_simulation_time_in_ms (32): 26,600 (-49%)
• l2_block_rollup_simulation_time_in_ms (128): 106,156 (-49%)
• l2_block_public_tx_process_time_in_ms (128): 51,584 (+28%)
• l2_block_processing_time_in_ms (8): 1,002 (-56%)
• l2_block_processing_time_in_ms (32): 3,868 (-56%)
• l2_block_processing_time_in_ms (128): 15,242 (-55%)
• note_successful_decrypting_time_in_ms (8): 330 (-53%)
• note_successful_decrypting_time_in_ms (32): 1,013 (-60%)
• note_successful_decrypting_time_in_ms (128): 3,908 (-59%)
• note_trial_decrypting_time_in_ms (8): 33.0 (+560%)

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 6c4e26cf 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	128 txs
l1_rollup_calldata_size_in_bytes	45,444	179,588	716,132
l1_rollup_calldata_gas	222,936	868,100	3,449,672
l1_rollup_execution_gas	842,023	3,595,208	22,205,041
l2_block_processing_time_in_ms	⚠️ 1,002 (-56%)	⚠️ 3,868 (-56%)	⚠️ 15,242 (-55%)
note_successful_decrypting_time_in_ms	⚠️ 330 (-53%)	⚠️ 1,013 (-60%)	⚠️ 3,908 (-59%)
note_trial_decrypting_time_in_ms	⚠️ 33.0 (+560%)	109 (+1%)	137 (+1%)
l2_block_building_time_in_ms	⚠️ 8,959 (-43%)	⚠️ 35,921 (-42%)	⚠️ 158,386 (-36%)
l2_block_rollup_simulation_time_in_ms	⚠️ 6,654 (-49%)	⚠️ 26,600 (-49%)	⚠️ 106,156 (-49%)
l2_block_public_tx_process_time_in_ms	2,267 (-10%)	9,199 (-8%)	⚠️ 51,584 (+28%)

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	⚠️ 12,444 (-56%)	⚠️ 23,717 (-58%)
note_history_successful_decrypting_time_in_ms	⚠️ 2,550 (-66%)	⚠️ 5,086 (-66%)
note_history_trial_decrypting_time_in_ms	125 (-1%)	147 (-5%)
node_database_size_in_bytes	1,631,607	1,101,191
pxe_database_size_in_bytes	27,188	54,187

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	⚠️ 47.4 (-47%)	61,697	18,841
private-kernel-ordering	⚠️ 23.4 (-57%)	24,233	8,089
base-rollup	⚠️ 862 (-61%)	656,309 (+3%)	811
root-rollup	⚠️ 39.0 (-60%)	4,072	1,097
private-kernel-inner	⚠️ 42.7 (-33%)	81,504	18,841
public-kernel-private-input	48.4 (-4%)	41,455	18,841
public-kernel-non-first-iteration	31.2 (-1%)	41,497	18,841
merge-rollup	0.877 (-10%)	2,592	873

Miscellaneous

Transaction sizes based on how many contracts are deployed in the tx.

Metric	0 deployed contracts	1 deployed contracts
tx_size_in_bytes	8,723	27,510 (-6%)

[benesjan]

LGTM. Happy it didn’t require too many changes. Our code might not be 💩🤣