weaselab/versioned-map
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Amortize cost of searching for continueKey

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This commit is contained in:
Andrew Noyes
2024-06-05 10:41:21 -07:00
parent 742f1da722
commit f1d10a1fed
3 changed files with 34 additions and 21 deletions
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4
Bench.cpp
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@@ -8,7 +8,7 @@ void monotonicallyIncreasing() {
ankerl::nanobench::Bench bench;
Facade facade{kWindow + 1};
bench.minEpochIterations(kWindow * 10);
bench.minEpochIterations(kWindow * 20);
bench.warmup(kWindow).run("monotonically increasing", [&] {
const int64_t remove = __builtin_bswap64(facade.getVersion() - kWindow);
@@ -106,4 +106,4 @@ void bulkFirstGeq() {
int main() {
monotonicallyIncreasing();
bulkFirstGeq();
}
}

37
README.md
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@@ -22,28 +22,29 @@ feature | weaselab | fdb |
# benchmarks
## weaselab
| ns/op | op/s | err% | total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
| 1,538.88 | 649,824.01 | 2.7% | 0.22 | `monotonically increasing`
| 1.25 | 798,888,023.37 | 0.0% | 0.01 | `*iter`
| 32.10 | 31,153,434.23 | 0.7% | 0.01 | `++iter`
| 31.08 | 32,178,831.30 | 0.3% | 0.01 | `--iter`
| 139.19 | 7,184,433.93 | 2.2% | 0.02 | `begin`
| 176.43 | 5,667,847.59 | 0.3% | 0.02 | `begin (firstGeq)`
| 54.56 | 18,329,336.92 | 0.4% | 0.01 | `end`
| 159.37 | 6,274,892.80 | 0.1% | 0.10 | `bulkFirstGeq`
| 153.55 | 6,512,408.74 | 0.1% | 0.09 | `bulkFirstGeq (latest version)`
| 1,225.88 | 815,738.46 | 0.7% | 0.31 | `monotonically increasing`
| 1.27 | 785,633,468.91 | 0.2% | 0.01 | `*iter`
| 29.18 | 34,265,322.00 | 0.4% | 0.01 | `++iter`
| 30.55 | 32,729,535.46 | 0.6% | 0.01 | `--iter`
| 155.38 | 6,435,768.30 | 0.4% | 0.04 | `begin`
| 181.88 | 5,498,125.78 | 0.5% | 0.04 | `begin (firstGeq)`
| 46.29 | 21,603,059.16 | 0.3% | 0.01 | `end`
| 169.68 | 5,893,481.63 | 0.1% | 0.10 | `bulkFirstGeq`
| 162.61 | 6,149,704.63 | 0.1% | 0.10 | `bulkFirstGeq (latest version)`
## fdb
| ns/op | op/s | err% | total | benchmark
|--------------------:|--------------------:|--------:|----------:|:----------
| 2,236.83 | 447,061.26 | 1.0% | 0.29 | `monotonically increasing`
| 2.11 | 473,370,596.42 | 0.9% | 0.01 | `*iter`
| 12.07 | 82,858,977.78 | 1.2% | 0.01 | `++iter`
| 8.54 | 117,158,071.80 | 0.9% | 0.01 | `--iter`
| 94.26 | 10,608,588.66 | 1.1% | 0.01 | `begin`
| 159.01 | 6,288,940.61 | 0.4% | 0.02 | `begin (firstGeq)`
| 73.47 | 13,610,276.41 | 0.9% | 0.01 | `end`
| 422.53 | 2,366,723.10 | 0.1% | 0.25 | `bulkFirstGeq`
| 365.13 | 2,738,758.86 | 0.1% | 0.22 | `bulkFirstGeq (latest version)`
| 2,237.52 | 446,923.66 | 0.6% | 0.56 | `monotonically increasing`
| 2.07 | 484,208,685.89 | 0.6% | 0.01 | `*iter`
| 9.91 | 100,926,329.70 | 0.5% | 0.01 | `++iter`
| 11.36 | 88,023,104.91 | 0.3% | 0.01 | `--iter`
| 87.70 | 11,402,839.76 | 0.2% | 0.02 | `begin`
| 110.58 | 9,043,264.46 | 0.2% | 0.03 | `begin (firstGeq)`
| 67.30 | 14,859,247.22 | 0.3% | 0.02 | `end`
| 411.72 | 2,428,853.18 | 0.1% | 0.25 | `bulkFirstGeq`
| 350.54 | 2,852,725.55 | 0.1% | 0.21 | `bulkFirstGeq (latest version)`

14
VersionedMap.cpp
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@@ -801,7 +801,19 @@ struct __attribute__((__visibility__("hidden"))) VersionedMap::Impl {
void printInOrderHelper(int64_t version, uint32_t node, int depth);
int accumulatedFuel = 0;
void scanAndRemoveOldEntries(int fuel) {
accumulatedFuel += fuel;
#ifdef NDEBUG
// This is here for performance reasons, since we want to amortize the cost
// of searching for continueKey. In tests, we want to exercise the rest of
// the code often.
if (accumulatedFuel < 500) {
return;
}
#endif
// Get a finger to the first entry > continueKey, or the last entry if
// continueKey is the empty string
if (latestRoot == 0) {
@@ -838,7 +850,7 @@ struct __attribute__((__visibility__("hidden"))) VersionedMap::Impl {
// Phew. Ok now we have a finger to the next entry to consider removing, and
// the range version terminated at this entry.
for (; fuel > 0; --fuel) {
for (; accumulatedFuel > 0; --accumulatedFuel) {
const auto &n = mm.base[finger.backNode()];
if (rangeVersion < 0 && std::max(n.entry->pointVersion,
n.entry->rangeVersion) < oldestVersion) {