root@srv-5gym-chalk:/home/bugtest# echo 3 > /proc/sys/vm/drop_caches 
root@srv-5gym-chalk:/home/bugtest# s=/lib; d=1; rm -rf "$d"; echo -n "Copying $s to $d: "; while /usr/bin/time -f %e cp -a "$s" "$d"; do s=$d; d=$((($d+1)%10)); rm -rf "$d"; echo -n "Copying $s to $d: "; done
Copying /lib to 1: 8.61
Copying 1 to 2: 9.59
Copying 2 to 3: 10.01
Copying 3 to 4: 10.09
Copying 4 to 5: 10.39
Copying 5 to 6: 10.31
Copying 6 to 7: 11.79
Copying 7 to 8: 12.70
Copying 8 to 9: 14.26
Copying 9 to 0: 14.95
Copying 0 to 1: 21.04
Copying 1 to 2: 57.64
Copying 2 to 3: 383.68
Copying 3 to 4: