Benchmark table reader wiht nanoseconds
Summary: nanosecnods gave us better view of the performance, especially when some operations are fast so that micro seconds may only reveal less informative results.
Test Plan:
sample output:
./table_reader_bench --plain_table --time_unit=nanosecond
=======================================================================================================
InMemoryTableSimpleBenchmark: PlainTable num_key1: 4096 num_key2: 512 non_empty
=======================================================================================================
Histogram (unit: nanosecond):
Count: 6291456 Average: 475.3867 StdDev: 556.05
Min: 135.0000 Median: 400.1817 Max: 33370.0000
Percentiles: P50: 400.18 P75: 530.02 P99: 887.73 P99.9: 8843.26 P99.99: 9941.21
------------------------------------------------------
[ 120, 140 ) 2 0.000% 0.000%
[ 140, 160 ) 452 0.007% 0.007%
[ 160, 180 ) 13683 0.217% 0.225%
[ 180, 200 ) 54353 0.864% 1.089%
[ 200, 250 ) 101004 1.605% 2.694%
[ 250, 300 ) 729791 11.600% 14.294% ##
[ 300, 350 ) 616070 9.792% 24.086% ##
[ 350, 400 ) 1628021 25.877% 49.963% #####
[ 400, 450 ) 647220 10.287% 60.250% ##
[ 450, 500 ) 577206 9.174% 69.424% ##
[ 500, 600 ) 1168585 18.574% 87.999% ####
[ 600, 700 ) 506875 8.057% 96.055% ##
[ 700, 800 ) 147878 2.350% 98.406%
[ 800, 900 ) 42633 0.678% 99.083%
[ 900, 1000 ) 16304 0.259% 99.342%
[ 1000, 1200 ) 7811 0.124% 99.466%
[ 1200, 1400 ) 1453 0.023% 99.490%
[ 1400, 1600 ) 307 0.005% 99.494%
[ 1600, 1800 ) 81 0.001% 99.496%
[ 1800, 2000 ) 18 0.000% 99.496%
[ 2000, 2500 ) 8 0.000% 99.496%
[ 2500, 3000 ) 6 0.000% 99.496%
[ 3500, 4000 ) 3 0.000% 99.496%
[ 4000, 4500 ) 116 0.002% 99.498%
[ 4500, 5000 ) 1144 0.018% 99.516%
[ 5000, 6000 ) 1087 0.017% 99.534%
[ 6000, 7000 ) 2403 0.038% 99.572%
[ 7000, 8000 ) 9840 0.156% 99.728%
[ 8000, 9000 ) 12820 0.204% 99.932%
[ 9000, 10000 ) 3881 0.062% 99.994%
[ 10000, 12000 ) 135 0.002% 99.996%
[ 12000, 14000 ) 159 0.003% 99.998%
[ 14000, 16000 ) 58 0.001% 99.999%
[ 16000, 18000 ) 30 0.000% 100.000%
[ 18000, 20000 ) 14 0.000% 100.000%
[ 20000, 25000 ) 2 0.000% 100.000%
[ 25000, 30000 ) 2 0.000% 100.000%
[ 30000, 35000 ) 1 0.000% 100.000%
Reviewers: haobo, dhruba, sdong
CC: leveldb
Differential Revision: https://reviews.facebook.net/D16113
59cffe02c4