You can see both direct and cache read using command below:

$ sudo hdparm -Tt /dev/sda

 /dev/sda:
 Timing cached reads:   12540 MB in  2.00 seconds = 6277.67 MB/sec
 Timing buffered disk reads: 234 MB in  3.00 seconds =  77.98 MB/sec

#linux #benchmark #hdd #hdparm #sda