fread in faster in testChunkEngine

[BayRanger]

Hi, In testChunkEngine.cc，I run the code in the linux server, fread shows a better performance, while I thought given the conclusion from 3FS. AIO should provide a better performance. I also tried tuning the parameters, but the result is the same.
So is there any examples to illustrate that AIO could perform better performance than fread?

Creating test file... Running benchmarks... fread: 6972.07 MB/s AIO: 455.35 MB/s