Faiss Flat Index Much Slower

[tzheng8]

Hello Community,

Recenly I noticed that the FAISS Flat index is much slower (at least 10X to 100X Slower). Specifically, I am using Sagemaker studio from AWS for my deployment. I used faiss.write_index to write the flat index and then use faiss.read_index(index_path) to load it. Therefore, the index itself should remain unchanged. However, the index search time is much slower,
D, I = index.search(embedding , 50)

Previously, the search time for 75K queries is 2000 seconds. Right now, the search time for 1K queries is 500 seconds.

The only difference is that, the GPU instance is restarted and I re-installed faiss-GPU.
Could you please help? thank you!