weaselab/conflict-set
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Run skip list gc at 200% entry insertion rate

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This commit is contained in:
Andrew Noyes
2024-08-22 17:26:08 -07:00
parent ee3361952a
commit 764c31bbc8
1 changed files with 22 additions and 10 deletions
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30
SkipList.cpp
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@@ -423,18 +423,23 @@ public:
} }
void swap(SkipList &other) { std::swap(header, other.header); } void swap(SkipList &other) { std::swap(header, other.header); }
void addConflictRanges(const Finger *fingers, int rangeCount, // Returns the change in the number of entries
int64_t addConflictRanges(const Finger *fingers, int rangeCount,
Version version) { Version version) {
int64_t result = rangeCount;
for (int r = rangeCount - 1; r >= 0; r--) { for (int r = rangeCount - 1; r >= 0; r--) {
const Finger &startF = fingers[r * 2]; const Finger &startF = fingers[r * 2];
const Finger &endF = fingers[r * 2 + 1]; const Finger &endF = fingers[r * 2 + 1];
if (endF.found() == nullptr) if (endF.found() == nullptr) {
++result;
insert(endF, endF.finger[0]->getMaxVersion(0)); insert(endF, endF.finger[0]->getMaxVersion(0));
}
remove(startF, endF); result -= remove(startF, endF);
insert(startF, version); insert(startF, version);
} }
return result;
} }
void detectConflicts(ReadConflictRange *ranges, int count, void detectConflicts(ReadConflictRange *ranges, int count,
@@ -564,9 +569,10 @@ public:
} }
private: private:
void remove(const Finger &start, const Finger &end) { // Returns the number of entries removed
int64_t remove(const Finger &start, const Finger &end) {
if (start.finger[0] == end.finger[0]) if (start.finger[0] == end.finger[0])
return; return 0;
Node *x = start.finger[0]->getNext(0); Node *x = start.finger[0]->getNext(0);
@@ -575,13 +581,16 @@ private:
if (start.finger[i] != end.finger[i]) if (start.finger[i] != end.finger[i])
start.finger[i]->setNext(i, end.finger[i]->getNext(i)); start.finger[i]->setNext(i, end.finger[i]->getNext(i));
int64_t result = 0;
while (true) { while (true) {
Node *next = x->getNext(0); Node *next = x->getNext(0);
x->destroy(); x->destroy();
++result;
if (x == end.finger[0]) if (x == end.finger[0])
break; break;
x = next; x = next;
} }
return result;
} }
void insert(const Finger &f, Version version) { void insert(const Finger &f, Version version) {
@@ -772,17 +781,20 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
StringRef values[stripeSize]; StringRef values[stripeSize];
int64_t writeVersions[stripeSize / 2]; int64_t writeVersions[stripeSize / 2];
int ss = stringCount - (stripes - 1) * stripeSize; int ss = stringCount - (stripes - 1) * stripeSize;
int64_t entryDelta = 0;
for (int s = stripes - 1; s >= 0; s--) { for (int s = stripes - 1; s >= 0; s--) {
for (int i = 0; i * 2 < ss; ++i) { for (int i = 0; i * 2 < ss; ++i) {
const auto &w = combinedWriteConflictRanges[s * stripeSize / 2 + i]; const auto &w = combinedWriteConflictRanges[s * stripeSize / 2 + i];
values[i * 2] = w.first; values[i * 2] = w.first;
values[i * 2 + 1] = w.second; values[i * 2 + 1] = w.second;
keyUpdates += 3;
} }
skipList.find(values, fingers, temp, ss); skipList.find(values, fingers, temp, ss);
skipList.addConflictRanges(fingers, ss / 2, writeVersion); entryDelta += skipList.addConflictRanges(fingers, ss / 2, writeVersion);
ss = stripeSize; ss = stripeSize;
} }
// Run gc at least 200% the rate we're inserting entries
keyUpdates += std::max<int64_t>(entryDelta, 0) * 2;
} }
void setOldestVersion(int64_t oldestVersion) { void setOldestVersion(int64_t oldestVersion) {
@@ -792,7 +804,7 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
int temp; int temp;
std::span<const uint8_t> key = removalKey; std::span<const uint8_t> key = removalKey;
skipList.find(&key, &finger, &temp, 1); skipList.find(&key, &finger, &temp, 1);
skipList.removeBefore(oldestVersion, finger, std::exchange(keyUpdates, 10)); skipList.removeBefore(oldestVersion, finger, std::exchange(keyUpdates, 0));
removalArena = Arena(); removalArena = Arena();
removalKey = copyToArena( removalKey = copyToArena(
removalArena, {finger.getValue().data(), finger.getValue().size()}); removalArena, {finger.getValue().data(), finger.getValue().size()});
@@ -801,7 +813,7 @@ struct __attribute__((visibility("hidden"))) ConflictSet::Impl {
int64_t totalBytes = 0; int64_t totalBytes = 0;
private: private:
int64_t keyUpdates = 10; int64_t keyUpdates = 0;
Arena removalArena; Arena removalArena;
std::span<const uint8_t> removalKey; std::span<const uint8_t> removalKey;
int64_t oldestVersion; int64_t oldestVersion;