unexpected low qps on ssd machine, any thing wrong?

[secwang]

Init pegasus succeed
LevelDB: version 4.0
Date: Thu Nov 9 08:13:07 2017
CPU: 2 * Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz
CPUCache: 46080 KB
Keys: 16 bytes each
Values: 100 bytes each (100 bytes after compression)
Entries: 100000
Prefix: 0 bytes
Keys per prefix: 0
RawSize: 11.1 MB (estimated)
FileSize: 11.1 MB (estimated)
Writes per second: 0
Compression: NoCompression
Memtablerep: skip_list
Perf Level: 0
WARNING: Optimization is disabled: benchmarks unnecessarily slow
WARNING: Assertions are enabled; benchmarks unnecessarily slow

Thread Count Runtime QPS AvgLat P99Lat
1 10000 11.763 850 1176 2425
2 20000 20.256 987 2018 4953
3 30000 29.534 1015 2938 7817
4 40000 38.809 1030 3765 12794

[qinzuoyan]

Is it read or write? The result shows that the average latency is in range of [1,4] milliseconds, depending on the thread count.
These aspects may improve performance:

• build with -t release option
• use SSD instead of HDD

[secwang]

build with -t release, Thanks.
Thread Count Runtime QPS AvgLat P99Lat
1 10000 4.9163 2033 491 1377
2 20000 8.1208 2462 808 2443
3 30000 11.623 2580 1153 3607
4 40000 15.369 2602 1517 5742
5 50000 19.670 2541 1937 7728