More detailed comparison results are as follows:
+------------+-------------------------+--------------------------+
| bs=4K | randwrite | randread |
| iodepth=1 +------------+------------+-------------+------------+
| (iops) | cbd cache | bcache | cbd cache | bcache |
+------------+------------+------------+-------------+------------+
| numjobs=1 | 93652 | 38055 | 154101 | 142292 |
+------------+------------+------------+-------------+------------+
| numjobs=2 | 205255 | 79322 | 317143 | 221957 |
+------------+------------+------------+-------------+------------+
| numjobs=4 | 430588 | 124439 | 635760 | 513443 |
+------------+------------+------------+-------------+------------+
| numjobs=8 | 852865 | 160980 | 1226714 | 505911 |
+------------+------------+------------+-------------+------------+
| numjobs=16| 1140952 | 226094 | 2058178 | 996146 |
+------------+------------+------------+-------------+------------+
| numjobs=32| 1418989 | 214447 | 2892710 | 1361308 |
+------------+------------+------------+-------------+------------+
(4) better performance stablility (less stdev)
CBD Cache, through a streamlined design, simplifies and makes the IO
process more controllable, which allows for stable performance output.
For example, in CBD Cache, the writeback does not need to walk through
the indexing tree, meaning that the writeback process will not suffer
from increased IO latency due to conflict in the indexing tree.
