Hi, I have been doing a testing to see how Linux buffer cache and readahead algorithms perform for reading a file from a disk. My assumption is that: (1) when the file size is less than the available physical memory, buffer cache and readahead can give better performance even though extra sectors are read. This is due to the fact that the system has enough memory to buffer the whole file (2) when the system has less memory than the file size, buffer cache and readahead should have worse performance due to the overhead caused.
However for my testings, the performances are about the same regardless if the system has more memory (larger than the file size) or not. I can't quite understand this. Can anyone help me with this? I'm using kernel 2.6.18. Thanks in advance!!! Fei
