[dm-devel] bcache performance test problem

[Qinling]

Hi Kent,

I have tested bcache on my platform, but the result is not good. I think maybe the wrong config caused it. Would you pls help me to check the config, or give me some advice for bcache performance testing?

My SSD card is  a PCIe SSD card (about 120,000 IOPS), and I used 10GB.

I have download the code from git://evilpiepirate.org/~kent/linux-bcache.git.
The commands creating bcache is below:
make-bcache -B /dev/sdb8
make-bcache -C -w4k -b1M -writeback /dev/hioa5

I use FIO to test the seq./random IO performance, and the result is below:
write             read                    randwrite    randread
bcache               10809 KB/s    164502.5 KB/s     2713 KB/s    29640 KB/s
cache_hit_rate  80                  79                         94                92


And the basic test result is:
Write                   read                  randwrite             randread
HDD      81211.6 KB/s       172242 KB/s     2606 KB/s             1855 KB/s
SSD       250948.2 KB/s     813855 KB/s     238892.7 KB/s      657319.5 KB/s

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