[SPDK] Rocksdb over SPDK/Blobfs

Hi everyone,

I am running the rocksdb::RandomTransaction benchmark with *1 thread* with
the following specifications:

RocksDB:    version 5.14
Date:       Wed Nov 25 13:05:48 2020
CPU:        16 * Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz
CPUCache:   16384 KB
Keys:       16 bytes each
Values:     1024 bytes each (1024 bytes after compression)
Entries:    5000000
Prefix:    0 bytes
Keys per prefix:    0
RawSize:    4959.1 MB (estimated)
FileSize:   4959.1 MB (estimated)
Write rate: 0 bytes/second
Read rate: 0 ops/second
Compression: NoCompression
Memtablerep: skip_list
Perf Level: 1
-----------------------------------------------------------------------------------------------------------------------

When using the kernel NVMe driver I have better performance (x 5 times). In
particular the db_bench output is:
NVMe driver: randomtransaction :      *16.727 micros/op 59782 ops/sec;*
 1.5 MB/s (transactions:5000000 aborts:0)

SPDK: randomtransaction :      *71.226 micros/op 14039 ops/sec;*    0.3
MB/s (transactions:5000000 aborts:0)

I am using SPDK v18.01.1 and DPDK v18.02. The SPDK cache is 4GB and
apparently I cannot increase it in my platform.

I am not sure how to explain this behavior. I would appreciate any
help/comment on the result.

Thanks,
Dimitra

-- 
Giantsidi Dimitra

e-mail:dimitra.giantsidi(a)gmail.com