Andrew Noyes
be8ac879c5
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weaselab/conflict-set/pipeline/head This commit looks good
106 lines
3.7 KiB
Markdown
106 lines
3.7 KiB
Markdown
A data structure for optimistic concurrency control on ranges of bitwise-lexicographically-ordered keys.
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Intended to replace FoundationDB's skip list.
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Hardware for all benchmarks is a mac m1 2020.
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# FoundationDB's benchmark
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## Skip list
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```
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New conflict set: 1.927 sec
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0.649 Mtransactions/sec
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2.595 Mkeys/sec
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Detect only: 1.838 sec
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0.680 Mtransactions/sec
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2.721 Mkeys/sec
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Skiplist only: 1.256 sec
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0.995 Mtransactions/sec
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3.981 Mkeys/sec
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Performance counters:
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Build: 0.0381
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Add: 0.0499
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Detect: 1.84
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D.Sort: 0.411
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D.Combine: 0.0141
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D.CheckRead: 0.667
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D.CheckIntraBatch: 0.00673
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D.MergeWrite: 0.589
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D.RemoveBefore: 0.146
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```
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## Radix tree (this implementation)
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```
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New conflict set: 1.318 sec
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0.949 Mtransactions/sec
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3.795 Mkeys/sec
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Detect only: 1.202 sec
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1.040 Mtransactions/sec
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4.160 Mkeys/sec
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Skiplist only: 0.542 sec
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2.307 Mtransactions/sec
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9.227 Mkeys/sec
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Performance counters:
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Build: 0.0566
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Add: 0.058
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Detect: 1.2
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D.Sort: 0.411
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D.Combine: 0.0136
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D.CheckRead: 0.22
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D.CheckIntraBatch: 0.00659
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D.MergeWrite: 0.322
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D.RemoveBefore: 0.226
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```
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# Our benchmark
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## Skip list
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| ns/op | op/s | err% | total | benchmark
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|--------------------:|--------------------:|--------:|----------:|:----------
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| 257.12 | 3,889,241.18 | 0.2% | 0.01 | `point reads`
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| 276.38 | 3,618,145.21 | 0.3% | 0.01 | `prefix reads`
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| 494.19 | 2,023,531.84 | 0.2% | 0.01 | `range reads`
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| 451.22 | 2,216,229.54 | 1.3% | 0.01 | `point writes`
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| 435.80 | 2,294,622.46 | 0.3% | 0.01 | `prefix writes`
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| 246.67 | 4,053,999.27 | 4.2% | 0.02 | `range writes`
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| 555.46 | 1,800,304.91 | 0.9% | 0.01 | `monotonic increasing point writes`
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## Radix tree (this implementation)
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| ns/op | op/s | err% | total | benchmark
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|--------------------:|--------------------:|--------:|----------:|:----------
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| 19.40 | 51,554,711.61 | 0.2% | 0.01 | `point reads`
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| 57.10 | 17,514,573.13 | 0.4% | 0.01 | `prefix reads`
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| 215.65 | 4,637,096.77 | 0.4% | 0.01 | `range reads`
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| 27.52 | 36,340,784.38 | 0.2% | 0.01 | `point writes`
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| 42.16 | 23,720,515.40 | 0.7% | 0.01 | `prefix writes`
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| 48.33 | 20,691,082.14 | 2.7% | 0.01 | `range writes`
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| 87.93 | 11,372,164.55 | 2.5% | 0.01 | `monotonic increasing point writes`
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# "Real data" test
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Point queries only, best of three runs. Gc ratio is the ratio of time spent doing garbage collection to time spent adding writes or doing garbage collection. Lower is better.
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## skip list
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```
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Check: 11.3839 seconds, 328.404 MB/s, Add: 5.32878 seconds, 131.745 MB/s, Gc ratio: 45.5903%
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```
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## radix tree
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```
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Check: 2.55069 seconds, 1465.69 MB/s, Add: 2.08443 seconds, 336.801 MB/s, Gc ratio: 41.748%
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```
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## hash table
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(The hash table implementation doesn't work on range queries, and its purpose is to provide an idea of how fast point queries can be)
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```
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Check: 1.84205 seconds, 2029.54 MB/s, Add: 0.60281 seconds, 1164.61 MB/s, Gc ratio: 48.8159%
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```
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