Files
qdrant/lib/segment/benches/multi_vector_search.rs
Arnaud Gourlay c196d2eb1a Benches: use SmallRng instead of ChaCha12-based generators (#9887)
* Benches: use SmallRng instead of ChaCha12-based generators

All benchmarks used StdRng or rand::rng() (ThreadRng), both backed by the
ChaCha12 block cipher in rand 0.10. Benchmarks do not need crypto-strength
randomness, and several draw random values inside the timed closure, so
cipher work was included in the measurement itself.

Switch every bench target to SmallRng (Xoshiro256++), and key the HNSW
graph cache and sparse index cache by RNG algorithm so stale caches built
from the old generator are not reused against newly generated vectors.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Benches: replace free-function rand::random with local SmallRng

Addresses review: rand::random draws from the thread RNG (ChaCha12),
including inside the timed loop of the pq score benchmark.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-07-17 17:22:27 +02:00

155 lines
5.6 KiB
Rust

// Deprecated storage placement params (`on_disk`, `always_ram`, `on_disk_payload`) are still
// handled here for backward compatibility with the new `memory` parameter
#![allow(deprecated)]
use std::collections::HashMap;
use std::sync::Arc;
use std::sync::atomic::AtomicBool;
use common::budget::ResourcePermit;
use common::counter::hardware_counter::HardwareCounterCell;
use common::flags::FeatureFlags;
use common::progress_tracker::ProgressTracker;
use criterion::{BatchSize, Criterion, criterion_group, criterion_main};
use rand::prelude::SmallRng;
use rand::{Rng, SeedableRng};
use segment::data_types::vectors::{DEFAULT_VECTOR_NAME, only_default_multi_vector};
use segment::entry::entry_point::SegmentEntry;
use segment::fixtures::payload_fixtures::random_multi_vector;
use segment::index::VectorIndexRead;
use segment::index::hnsw_index::get_num_indexing_threads;
use segment::index::hnsw_index::hnsw::{HNSWIndex, HnswIndexOpenArgs};
use segment::segment_constructor::{VectorIndexBuildArgs, build_segment};
use segment::types::Distance::{Dot, Euclid};
use segment::types::{
Distance, HnswConfig, HnswGlobalConfig, Indexes, MultiVectorConfig, SegmentConfig,
SeqNumberType, VectorDataConfig, VectorStorageType,
};
use tempfile::Builder;
#[cfg(not(target_os = "windows"))]
mod prof;
const NUM_POINTS: usize = 10_000;
const NUM_VECTORS_PER_POINT: usize = 16;
const VECTOR_DIM: usize = 128;
const TOP: usize = 10;
// intent: bench `search` without filter
fn multi_vector_search_benchmark(c: &mut Criterion) {
let mut group = c.benchmark_group("multi-vector-search-group");
let mut rnd = SmallRng::seed_from_u64(42);
let hnsw_index = make_segment_index(&mut rnd, Dot);
group.bench_function("hnsw-multivec-search-dot", |b| {
b.iter_batched(
|| random_multi_vector(&mut rnd, VECTOR_DIM, NUM_VECTORS_PER_POINT).into(),
|query| {
let results = hnsw_index
.search(&[&query], None, TOP, None, &Default::default())
.unwrap();
assert_eq!(results[0].len(), TOP);
},
BatchSize::SmallInput,
)
});
let hnsw_index = make_segment_index(&mut rnd, Euclid);
group.bench_function("hnsw-multivec-search-euclidean", |b| {
b.iter_batched(
|| random_multi_vector(&mut rnd, VECTOR_DIM, NUM_VECTORS_PER_POINT).into(),
|query| {
let results = hnsw_index
.search(&[&query], None, TOP, None, &Default::default())
.unwrap();
assert_eq!(results[0].len(), TOP);
},
BatchSize::SmallInput,
)
});
group.finish();
}
fn make_segment_index<R: Rng + ?Sized>(rng: &mut R, distance: Distance) -> HNSWIndex {
let stopped = AtomicBool::new(false);
let segment_dir = Builder::new().prefix("data_dir").tempdir().unwrap();
let hnsw_dir = Builder::new().prefix("hnsw_dir").tempdir().unwrap();
let segment_config = SegmentConfig {
vector_data: HashMap::from([(
DEFAULT_VECTOR_NAME.to_owned(),
VectorDataConfig {
size: VECTOR_DIM,
distance,
storage_type: VectorStorageType::default(),
index: Indexes::Plain {},
quantization_config: None,
multivector_config: Some(MultiVectorConfig::default()), // uses multivec config
datatype: None,
},
)]),
sparse_vector_data: Default::default(),
payload_storage_type: Default::default(),
};
let hw_counter = HardwareCounterCell::new();
let (mut segment, _) = build_segment(segment_dir.path(), &segment_config, None, true).unwrap();
for n in 0..NUM_POINTS {
let idx = (n as u64).into();
let multi_vec = random_multi_vector(rng, VECTOR_DIM, NUM_VECTORS_PER_POINT);
let named_vectors = only_default_multi_vector(&multi_vec);
segment
.upsert_point(n as SeqNumberType, idx, named_vectors, &hw_counter)
.unwrap();
}
// build HNSW index
let hnsw_config = HnswConfig {
memory: None,
m: 8,
ef_construct: 16,
full_scan_threshold: 10, // low value to trigger index usage by default
max_indexing_threads: 0,
on_disk: None,
payload_m: None,
inline_storage: None,
};
let permit_cpu_count = get_num_indexing_threads(hnsw_config.max_indexing_threads);
let permit = Arc::new(ResourcePermit::dummy(permit_cpu_count as u32));
let vector_storage = &segment.vector_data[DEFAULT_VECTOR_NAME].vector_storage;
let quantized_vectors = &segment.vector_data[DEFAULT_VECTOR_NAME].quantized_vectors;
let hnsw_index = HNSWIndex::build(
HnswIndexOpenArgs {
path: hnsw_dir.path(),
id_tracker: segment.id_tracker.clone(),
vector_storage: vector_storage.clone(),
quantized_vectors: quantized_vectors.clone(),
payload_index: segment.payload_index.clone(),
hnsw_config,
},
VectorIndexBuildArgs {
permit,
old_indices: &[],
gpu_device: None,
stopped: &stopped,
rng,
hnsw_global_config: &HnswGlobalConfig::default(),
feature_flags: FeatureFlags::default(),
progress: ProgressTracker::new_for_test(),
},
)
.unwrap();
hnsw_index.populate().unwrap();
hnsw_index
}
criterion_group! {
name = benches;
config = Criterion::default().with_profiler(prof::FlamegraphProfiler::new(100));
targets = multi_vector_search_benchmark
}
criterion_main!(benches);