You’d be surprised how difficult it can be to create such a scenario and detect when you do, especially using a synthetic benchmark. In terms of regular io, di

You’d be surprised how difficult it can be to create such a scenario and detect when you do, especially using a synthetic benchmark. In terms of regular io, did you remember to do O_DIRECT? Also yes, I/O paths are slower than mmap for pure throughput in most cases. Databases are a special snowflake though. In some ways you’d want the I/O layer in the kernel like with a filesystem which is why databases typically go the other way and try to bypass the kernel to keep their code in user space