Files
faiss/benchs/bench_flat_l2_panorama.py
T
Akash Nayar 76c67b7b73 Update default Panorama batch size to 1024 (#5441)
Summary:
## Changes

This PR unifies the default Panorama batch size to 1024 going forward. This was shown to offer better performance than the current values ([paper](https://arxiv.org/abs/2510.00566), figure 11).

## Performance

### IVFFlatPanorama

SIFT1M
| nprobe | qps_before | qps_after | speedup |
|---|---|---|---|
| 1 | 5980.4 | 6343.7 | 1.06x |
| 2 | 3537.7 | 3933.2 | 1.11x |
| 4 | 2105.4 | 2419.9 | 1.15x |
| 8 | 1245.2 | 1466.4 | 1.18x |
| 16 | 729.2 | 887.4 | 1.22x |
| 32 | 429.6 | 538.0 | 1.25x |
| 64 | 249.0 | 319.3 | 1.28x |

GIST1M
| nprobe | qps_before | qps_after | speedup |
|---|---|---|---|
| 1 | 1826.0 | 1494.7 | 0.82x |
| 2 | 1091.0 | 1001.7 | 0.92x |
| 4 | 642.2 | 639.0 | 0.99x |
| 8 | 368.7 | 392.7 | 1.07x |
| 16 | 212.2 | 233.9 | 1.10x |
| 32 | 122.2 | 138.6 | 1.13x |
| 64 | 71.3 | 82.6 | 1.16x |

## FlatL2Panorama

SIFT1M
| qps_before | qps_after | speedup |
|---|---|---|
| 124.8 | 133.4 | 1.07x |

GIST1M
| qps_before | qps_after | speedup |
|---|---|---|
| 44.1 | 46.2 | 1.05x |

Pull Request resolved: https://github.com/facebookresearch/faiss/pull/5441

Reviewed By: alibeklfc

Differential Revision: D114387063

Pulled By: mnorris11

fbshipit-source-id: b71ba6ced074c4998aee3183df236b692626cd34
2026-08-03 10:53:18 -07:00

108 lines
2.4 KiB
Python

# Copyright (c) Meta Platforms, Inc. and affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
import argparse
import multiprocessing as mp
import time
import faiss
import matplotlib.pyplot as plt
import numpy as np
try:
from faiss.contrib.datasets_fb import DatasetSIFT1M, DatasetGIST1M
except ImportError:
from faiss.contrib.datasets import DatasetSIFT1M, DatasetGIST1M
parser = argparse.ArgumentParser()
parser.add_argument("--dataset", default="gist1m", choices=["sift1m", "gist1m"])
args = parser.parse_args()
if args.dataset == "sift1m":
ds = DatasetSIFT1M()
else:
ds = DatasetGIST1M()
nq = 10
xq = ds.get_queries()[:nq]
xb = ds.get_database()
gt = ds.get_groundtruth()[:nq]
xt = ds.get_train()
nb, d = xb.shape
nt, d = xt.shape
k = 10
gt = gt[:, :k]
def eval_qps(index):
faiss.cvar.indexPanorama_stats.reset()
t0 = time.time()
_, I = index.search(xq, k=k)
t = time.time() - t0
speed = t * 1000 / nq # ms/query
qps = 1000 / speed
corrects = (gt == I).sum()
recall = corrects / (nq * k)
ratio_dims_scanned = faiss.cvar.indexPanorama_stats.ratio_dims_scanned
print(
f"\tRecall@{k}: {recall:.6f}, speed: {speed:.6f} ms/query, "
f"dims scanned: {ratio_dims_scanned * 100:.2f}%"
)
return recall, qps
def build_index(name):
index = faiss.index_factory(d, name)
faiss.omp_set_num_threads(mp.cpu_count())
index.train(xt)
index.add(xb)
faiss.omp_set_num_threads(1)
return index
nlevels = 16 if args.dataset == "gist1m" else 8
plt.figure(figsize=(8, 6), dpi=80)
names = [
"Flat",
f"PCA{d},FlatL2Panorama{nlevels}",
]
labels = []
qps_values = []
for name in names:
print(f"======{name}")
index = build_index(name)
recall, qps = eval_qps(index)
labels.append(f"{name}\n(r@{recall:.3f})")
qps_values.append(qps)
x = np.arange(len(names))
plt.bar(x, qps_values, color=["#1f77b4", "#ff7f0e"])
speedup = qps_values[1] / qps_values[0]
ax = plt.gca()
ax.text(
x[1],
qps_values[1] * 1.01,
f"{speedup:.2f}x",
ha="center",
va="bottom",
)
plt.xticks(x, labels, rotation=0)
plt.ylabel("QPS")
dataset_label = args.dataset.upper()
plt.title(f"Flat Indexes on {dataset_label}")
plt.tight_layout()
plt.savefig(f"bench_flat_l2_panorama_{args.dataset}.png", bbox_inches="tight")