141 lines
4.5 KiB
C++
141 lines
4.5 KiB
C++
/*
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* HighContentionPrefixAllocator.actor.h
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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// When actually compiled (NO_INTELLISENSE), include the generated version of this file. In intellisense use the source
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// version.
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#if defined(NO_INTELLISENSE) && !defined(FDBCLIENT_HIGHCONTENTIONPREFIXALLOCATOR_ACTOR_G_H)
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#define FDBCLIENT_HIGHCONTENTIONPREFIXALLOCATOR_ACTOR_G_H
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#include "fdbclient/HighContentionPrefixAllocator.actor.g.h"
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#elif !defined(FDBCLIENT_HIGHCONTENTIONPREFIXALLOCATOR_ACTOR_H)
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#define FDBCLIENT_HIGHCONTENTIONPREFIXALLOCATOR_ACTOR_H
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#include "fdbclient/ClientBooleanParams.h"
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#include "fdbclient/CommitTransaction.h"
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#include "fdbclient/FDBOptions.g.h"
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#include "fdbclient/Subspace.h"
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#include "flow/UnitTest.h"
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#include "flow/actorcompiler.h" // This must be the last #include.
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class HighContentionPrefixAllocator {
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public:
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HighContentionPrefixAllocator(Subspace subspace) : counters(subspace.get(0)), recent(subspace.get(1)) {}
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template <class TransactionT>
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Future<Standalone<StringRef>> allocate(Reference<TransactionT> tr) {
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return allocate(this, tr);
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}
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static int64_t windowSize(int64_t start) {
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if (start < 255) {
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return 64;
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}
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if (start < 65535) {
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return 1024;
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}
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return 8192;
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}
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private:
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Subspace counters;
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Subspace recent;
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ACTOR template <class TransactionT>
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Future<Standalone<StringRef>> allocate(HighContentionPrefixAllocator* self, Reference<TransactionT> tr) {
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state int64_t start = 0;
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state int64_t window = 0;
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loop {
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RangeResult range =
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wait(safeThreadFutureToFuture(tr->getRange(self->counters.range(), 1, Snapshot::True, Reverse::True)));
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if (range.size() > 0) {
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start = self->counters.unpack(range[0].key).getInt(0);
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}
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state bool windowAdvanced = false;
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loop {
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// if thread safety is needed, this should be locked {
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if (windowAdvanced) {
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tr->clear(KeyRangeRef(self->counters.key(), self->counters.get(start).key()));
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tr->setOption(FDBTransactionOptions::NEXT_WRITE_NO_WRITE_CONFLICT_RANGE);
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tr->clear(KeyRangeRef(self->recent.key(), self->recent.get(start).key()));
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}
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int64_t inc = 1;
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tr->atomicOp(self->counters.get(start).key(), StringRef((uint8_t*)&inc, 8), MutationRef::AddValue);
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Future<Optional<Value>> countFuture =
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safeThreadFutureToFuture(tr->get(self->counters.get(start).key(), Snapshot::True));
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// }
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Optional<Value> countValue = wait(countFuture);
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int64_t count = 0;
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if (countValue.present()) {
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if (countValue.get().size() != 8) {
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throw invalid_directory_layer_metadata();
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}
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count = *(int64_t*)countValue.get().begin();
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}
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window = HighContentionPrefixAllocator::windowSize(start);
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if (count * 2 < window) {
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break;
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}
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start += window;
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windowAdvanced = true;
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}
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loop {
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state int64_t candidate = deterministicRandom()->randomInt(start, start + window);
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// if thread safety is needed, this should be locked {
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state Future<RangeResult> latestCounterFuture =
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safeThreadFutureToFuture(tr->getRange(self->counters.range(), 1, Snapshot::True, Reverse::True));
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state Future<Optional<Value>> candidateValueFuture =
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safeThreadFutureToFuture(tr->get(self->recent.get(candidate).key()));
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tr->setOption(FDBTransactionOptions::NEXT_WRITE_NO_WRITE_CONFLICT_RANGE);
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tr->set(self->recent.get(candidate).key(), ValueRef());
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// }
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wait(success(latestCounterFuture) && success(candidateValueFuture));
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int64_t currentWindowStart = 0;
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if (latestCounterFuture.get().size() > 0) {
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currentWindowStart = self->counters.unpack(latestCounterFuture.get()[0].key).getInt(0);
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}
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if (currentWindowStart > start) {
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break;
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}
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if (!candidateValueFuture.get().present()) {
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tr->addWriteConflictRange(singleKeyRange(self->recent.get(candidate).key()));
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return Tuple().append(candidate).pack();
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}
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}
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}
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}
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};
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#include "flow/unactorcompiler.h"
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#endif |