This is much better than skiplist and slist.
BenchmarkReadWrite/frac_0-8 3000000 537 ns/op
BenchmarkReadWrite/frac_1-8 3000000 503 ns/op
BenchmarkReadWrite/frac_2-8 3000000 492 ns/op
BenchmarkReadWrite/frac_3-8 3000000 475 ns/op
BenchmarkReadWrite/frac_4-8 3000000 440 ns/op
BenchmarkReadWrite/frac_5-8 5000000 442 ns/op
BenchmarkReadWrite/frac_6-8 5000000 380 ns/op
BenchmarkReadWrite/frac_7-8 5000000 338 ns/op
BenchmarkReadWrite/frac_8-8 5000000 294 ns/op
BenchmarkReadWrite/frac_9-8 10000000 268 ns/op
BenchmarkReadWrite/frac_10-8 100000000 26.3 ns/op
And even better than a simple map with read-write lock:
BenchmarkReadWriteMap/frac_0-8 2000000 774 ns/op
BenchmarkReadWriteMap/frac_1-8 2000000 647 ns/op
BenchmarkReadWriteMap/frac_2-8 3000000 605 ns/op
BenchmarkReadWriteMap/frac_3-8 3000000 603 ns/op
BenchmarkReadWriteMap/frac_4-8 3000000 556 ns/op
BenchmarkReadWriteMap/frac_5-8 3000000 472 ns/op
BenchmarkReadWriteMap/frac_6-8 3000000 476 ns/op
BenchmarkReadWriteMap/frac_7-8 3000000 457 ns/op
BenchmarkReadWriteMap/frac_8-8 5000000 444 ns/op
BenchmarkReadWriteMap/frac_9-8 5000000 361 ns/op
BenchmarkReadWriteMap/frac_10-8 10000000 212 ns/op
Command used
rm -Rf tmp && /usr/bin/time -l ./populate -keys_mil 10
For pprof results, we run without using /usr/bin/time. There are four runs below.
Results seem to vary quite a bit between runs.
1311.53MB of 1338.69MB total (97.97%)
Dropped 30 nodes (cum <= 6.69MB)
Showing top 10 nodes out of 37 (cum >= 12.50MB)
flat flat% sum% cum cum%
523.04MB 39.07% 39.07% 523.04MB 39.07% github.com/dgraph-io/badger/skl.(*Skiplist).Put
184.51MB 13.78% 52.85% 184.51MB 13.78% runtime.stringtoslicebyte
166.01MB 12.40% 65.25% 689.04MB 51.47% github.com/dgraph-io/badger/mem.(*Table).Put
165MB 12.33% 77.58% 165MB 12.33% runtime.convT2E
116.92MB 8.73% 86.31% 116.92MB 8.73% bytes.makeSlice
62.50MB 4.67% 90.98% 62.50MB 4.67% main.newValue
34.50MB 2.58% 93.56% 34.50MB 2.58% github.com/dgraph-io/badger/table.(*BlockIterator).parseKV
25.50MB 1.90% 95.46% 100.06MB 7.47% github.com/dgraph-io/badger/y.(*MergeIterator).Next
21.06MB 1.57% 97.04% 21.06MB 1.57% github.com/dgraph-io/badger/table.(*Table).read
12.50MB 0.93% 97.97% 12.50MB 0.93% github.com/dgraph-io/badger/table.header.Encode
128.31 real 329.37 user 17.11 sys
3355660288 maximum resident set size
0 average shared memory size
0 average unshared data size
0 average unshared stack size
2203080 page reclaims
764 page faults
0 swaps
275 block input operations
76 block output operations
0 messages sent
0 messages received
0 signals received
49173 voluntary context switches
599922 involuntary context switches
1963.13MB of 2026.09MB total (96.89%)
Dropped 29 nodes (cum <= 10.13MB)
Showing top 10 nodes out of 41 (cum >= 185.62MB)
flat flat% sum% cum cum%
658.05MB 32.48% 32.48% 658.05MB 32.48% github.com/dgraph-io/badger/skl.glob..func1
297.51MB 14.68% 47.16% 297.51MB 14.68% runtime.convT2E
257.51MB 12.71% 59.87% 257.51MB 12.71% runtime.stringtoslicebyte
249.01MB 12.29% 72.16% 1007.06MB 49.70% github.com/dgraph-io/badger/mem.(*Table).Put
142.43MB 7.03% 79.19% 142.43MB 7.03% bytes.makeSlice
100MB 4.94% 84.13% 758.05MB 37.41% github.com/dgraph-io/badger/skl.newNode
99.50MB 4.91% 89.04% 99.50MB 4.91% main.newValue
75MB 3.70% 92.74% 75MB 3.70% github.com/dgraph-io/badger/table.(*BlockIterator).parseKV
44.62MB 2.20% 94.94% 44.62MB 2.20% github.com/dgraph-io/badger/table.(*Table).read
39.50MB 1.95% 96.89% 185.62MB 9.16% github.com/dgraph-io/badger/y.(*MergeIterator).Next
135.58 real 374.29 user 17.65 sys
3740614656 maximum resident set size
0 average shared memory size
0 average unshared data size
0 average unshared stack size
2276566 page reclaims
770 page faults
0 swaps
128 block input operations
90 block output operations
0 messages sent
0 messages received
0 signals received
46434 voluntary context switches
597049 involuntary context switches