[Bug]: It takes long time to build index for Float16Vector about milvus HOT 3 OPEN

import random
import time

import numpy as np

from pymilvus import (
    connections,
    FieldSchema, CollectionSchema, DataType,
    Collection,
    utility,
)


HOST = 'localhost'
PORT = '19530'

connections.connect(host=HOST, port=PORT)

F16_COLLECTION = "f16_col"

DIM = 768
METRIC_TYPE = "L2"

ID_FIELD = "id"
VECTOR_FIELD = "vector"

def gen_fp16_vectors(num):
    raw_vectors = []
    fp16_vectors = []
    for _ in range(num):
        raw_vector = [random.random() for _ in range(DIM)]
        raw_vectors.append(raw_vector)
        fp16_vector = np.array(raw_vector, dtype=np.float16)
        fp16_vectors.append(fp16_vector)
    return raw_vectors, fp16_vectors

def create_collection():
    if utility.has_collection(F16_COLLECTION):
        utility.drop_collection(F16_COLLECTION)

    fields = [
        FieldSchema(name="id", dtype=DataType.INT64, is_primary=True, auto_id=True),
        FieldSchema(name="vector", dtype=DataType.FLOAT16_VECTOR, dim=DIM),
    ]
    schema = CollectionSchema(fields=fields)
    collection = Collection(name=F16_COLLECTION, schema=schema)
    print(f"Collection '{F16_COLLECTION}' created")


def prepare_data():
    collection_16 = Collection(name=F16_COLLECTION)
    count = 10000
    for i in range(100):
        raw_vectors, fp16_vectors = gen_fp16_vectors(count)
        collection_16.insert(data=[
            fp16_vectors,
        ])
        print(f"insert batch {i}")
    print("insert done")

    time.sleep(5)
    collection_16.flush()
    print("flush done")

    start = time.time()
    index_params = {
        'metric_type': METRIC_TYPE,
        'index_type': "HNSW",
        'params': {"M": 8, "efConstruction": 200},
    }
    collection_16.create_index(field_name=VECTOR_FIELD, index_params=index_params)
    utility.wait_for_index_building_complete(collection_name=F16_COLLECTION)
    print("index done")

    end = time.time()
    print(f"fp16 index time cost: {end-start} seconds")


if __name__ == '__main__':
    create_collection()
    prepare_data()