[Resend]Re: [PATCH] [v26,1/4] scsi: ufs: Introduce HPB feature

The Following is experiment environment:
- kernel version: 4.4.0
- RAM: 8GB
- UFS 2.1 (64GB)

Result:
+-------+----------+----------+-------+
| cycle | baseline | with HPB | diff  |
+-------+----------+----------+-------+
| 1     | 272.4    | 264.9    | -7.5  |
| 2     | 250.4    | 248.2    | -2.2  |
| 3     | 226.2    | 215.6    | -10.6 |
| 4     | 230.6    | 214.8    | -15.8 |
| 5     | 232.0    | 218.1    | -13.9 |
| 6     | 231.9    | 212.6    | -19.3 |
+-------+----------+----------+-------+

We also measured HPB performance using iozone.
Here is my iozone script:
iozone -r 4k -+n -i2 -ecI -t 16 -l 16 -u 16
-s $IO_RANGE/16 -F mnt/tmp_1 mnt/tmp_2 mnt/tmp_3 mnt/tmp_4 mnt/tmp_5
mnt/tmp_6 mnt/tmp_7 mnt/tmp_8 mnt/tmp_9 mnt/tmp_10 mnt/tmp_11 mnt/tmp_12
mnt/tmp_13 mnt/tmp_14 mnt/tmp_15 mnt/tmp_16

Result:
+----------+--------+---------+
| IO range | HPB on | HPB off |
+----------+--------+---------+
|   1 GB   | 294.8  | 300.87  |
|   4 GB   | 293.51 | 179.35  |
|   8 GB   | 294.85 | 162.52  |
|  16 GB   | 293.45 | 156.26  |
|  32 GB   | 277.4  | 153.25  |
+----------+--------+---------+

According to Samsung's iozone test result, HPB is going to boost random 
performance of rom on mobile, we believe it will help our customers on 
several occasions.

WangQing