For benchmarking purposes it makes sense to clear the caches, the linux kernel
creates for us. An additional
sync beforehand makes sure that everything is
committed to disk (dirty objects will not be freed).
sync sudo sysctl vm.drop_caches=3
sync echo 3 | sudo tee /proc/sys/vm/drop_caches >/dev/null
This will drop the pagecache, dentries and inodes.