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Posted to github@arrow.apache.org by GitBox <gi...@apache.org> on 2021/07/12 06:59:36 UTC
[GitHub] [arrow] projjal commented on a change in pull request #10465: ARROW-12986: [C++][Gandiva] Implement new cache eviction policy algorithm in Gandiva
projjal commented on a change in pull request #10465:
URL: https://github.com/apache/arrow/pull/10465#discussion_r667536039
##########
File path: cpp/src/gandiva/greedy_dual_size_cache.h
##########
@@ -0,0 +1,150 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <queue>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+
+// modified cache to support evict policy using the GreedyDual-Size algorithm.
+namespace gandiva {
+// Defines a base value object supported on the cache that may contain properties
+template <typename ValueType>
+class ValueCacheObject {
+ public:
+ explicit ValueCacheObject(ValueType module, uint64_t cost)
+ : module(module), cost(cost) {}
+ ValueCacheObject() = default;
+ ValueType module;
+ uint64_t cost;
+ bool operator<(const ValueCacheObject& other) const { return this->cost < other.cost; }
+};
+
+// a particular LRU based cache which evicts the least recently used item
+// considering the different costs for each entry.
+template <class Key, class Value>
+class GreedyDualSizeCache {
+ // inner class to define the priority item
+ class PriorityItem {
+ public:
+ PriorityItem(uint64_t actual_priority, uint64_t original_priority, Key key)
+ : actual_priority(actual_priority),
+ original_priority(original_priority),
+ cache_key(key) {}
+ // this ensure that the items with low priority stays in the beginning of the queue,
+ // so it can be the one removed by evict operation
+ bool operator<(const PriorityItem& other) const {
+ return this->actual_priority < other.actual_priority;
+ }
+ uint64_t actual_priority;
+ uint64_t original_priority;
+ Key cache_key;
+ };
+
+ public:
+ struct hasher {
+ template <typename I>
+ std::size_t operator()(const I& i) const {
+ return i.Hash();
+ }
+ };
+ // a map from 'key' to a pair of Value and a pointer to the priority value
+ using map_type = std::unordered_map<
+ Key, std::pair<ValueCacheObject<Value>, typename std::set<PriorityItem>::iterator>,
+ hasher>;
+
+ explicit GreedyDualSizeCache(size_t capacity) : cache_capacity_(capacity) {
+ this->inflation_cost_ = 0;
Review comment:
better put it in the initializer list
##########
File path: cpp/src/gandiva/greedy_dual_size_cache.h
##########
@@ -0,0 +1,150 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <queue>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+
+// modified cache to support evict policy using the GreedyDual-Size algorithm.
+namespace gandiva {
+// Defines a base value object supported on the cache that may contain properties
+template <typename ValueType>
+class ValueCacheObject {
+ public:
+ explicit ValueCacheObject(ValueType module, uint64_t cost)
+ : module(module), cost(cost) {}
+ ValueCacheObject() = default;
+ ValueType module;
+ uint64_t cost;
+ bool operator<(const ValueCacheObject& other) const { return this->cost < other.cost; }
+};
+
+// a particular LRU based cache which evicts the least recently used item
+// considering the different costs for each entry.
+template <class Key, class Value>
+class GreedyDualSizeCache {
+ // inner class to define the priority item
+ class PriorityItem {
+ public:
+ PriorityItem(uint64_t actual_priority, uint64_t original_priority, Key key)
+ : actual_priority(actual_priority),
+ original_priority(original_priority),
+ cache_key(key) {}
+ // this ensure that the items with low priority stays in the beginning of the queue,
+ // so it can be the one removed by evict operation
+ bool operator<(const PriorityItem& other) const {
+ return this->actual_priority < other.actual_priority;
+ }
+ uint64_t actual_priority;
+ uint64_t original_priority;
+ Key cache_key;
+ };
+
+ public:
+ struct hasher {
+ template <typename I>
+ std::size_t operator()(const I& i) const {
+ return i.Hash();
+ }
+ };
+ // a map from 'key' to a pair of Value and a pointer to the priority value
+ using map_type = std::unordered_map<
+ Key, std::pair<ValueCacheObject<Value>, typename std::set<PriorityItem>::iterator>,
+ hasher>;
+
+ explicit GreedyDualSizeCache(size_t capacity) : cache_capacity_(capacity) {
+ this->inflation_cost_ = 0;
+ }
+
+ GreedyDualSizeCache<Key, Value>() : cache_capacity_(capacity) {}
+
+ ~GreedyDualSizeCache() = default;
+
+ size_t size() const { return map_.size(); }
+
+ size_t capacity() const { return this->cache_capacity_; }
+
+ bool empty() const { return map_.empty(); }
+
+ bool contains(const Key& key) { return map_.find(key) != map_.end(); }
+
+ void insert(const Key& key, const ValueCacheObject<Value>& value) {
+ typename map_type::iterator i = map_.find(key);
+ // check if element is not in the cache to add it
+ if (i == map_.end()) {
+ // insert item into the cache, but first check if it is full, to evict an item
+ // if it is necessary
+ if (size() >= this->cache_capacity_) {
Review comment:
nit: lets not use the "this" pointer here and elsewhere unless needed to prevent ambiguity
##########
File path: cpp/src/gandiva/greedy_dual_size_cache.h
##########
@@ -0,0 +1,150 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <queue>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+
+// modified cache to support evict policy using the GreedyDual-Size algorithm.
+namespace gandiva {
+// Defines a base value object supported on the cache that may contain properties
+template <typename ValueType>
+class ValueCacheObject {
+ public:
+ explicit ValueCacheObject(ValueType module, uint64_t cost)
+ : module(module), cost(cost) {}
+ ValueCacheObject() = default;
+ ValueType module;
+ uint64_t cost;
+ bool operator<(const ValueCacheObject& other) const { return this->cost < other.cost; }
+};
+
+// a particular LRU based cache which evicts the least recently used item
+// considering the different costs for each entry.
+template <class Key, class Value>
+class GreedyDualSizeCache {
+ // inner class to define the priority item
+ class PriorityItem {
+ public:
+ PriorityItem(uint64_t actual_priority, uint64_t original_priority, Key key)
+ : actual_priority(actual_priority),
+ original_priority(original_priority),
+ cache_key(key) {}
+ // this ensure that the items with low priority stays in the beginning of the queue,
+ // so it can be the one removed by evict operation
+ bool operator<(const PriorityItem& other) const {
+ return this->actual_priority < other.actual_priority;
+ }
+ uint64_t actual_priority;
+ uint64_t original_priority;
+ Key cache_key;
+ };
+
+ public:
+ struct hasher {
+ template <typename I>
+ std::size_t operator()(const I& i) const {
+ return i.Hash();
+ }
+ };
+ // a map from 'key' to a pair of Value and a pointer to the priority value
+ using map_type = std::unordered_map<
+ Key, std::pair<ValueCacheObject<Value>, typename std::set<PriorityItem>::iterator>,
+ hasher>;
+
+ explicit GreedyDualSizeCache(size_t capacity) : cache_capacity_(capacity) {
+ this->inflation_cost_ = 0;
+ }
+
+ GreedyDualSizeCache<Key, Value>() : cache_capacity_(capacity) {}
+
+ ~GreedyDualSizeCache() = default;
+
+ size_t size() const { return map_.size(); }
+
+ size_t capacity() const { return this->cache_capacity_; }
+
+ bool empty() const { return map_.empty(); }
+
+ bool contains(const Key& key) { return map_.find(key) != map_.end(); }
+
+ void insert(const Key& key, const ValueCacheObject<Value>& value) {
+ typename map_type::iterator i = map_.find(key);
+ // check if element is not in the cache to add it
+ if (i == map_.end()) {
+ // insert item into the cache, but first check if it is full, to evict an item
+ // if it is necessary
+ if (size() >= this->cache_capacity_) {
+ evict();
+ }
+
+ // insert the new item
+ auto iter = this->priority_set_.insert(
+ PriorityItem(value.cost + this->inflation_cost_, value.cost, key));
+ // save on map the value and the priority item iterator position
+ map_[key] = std::make_pair(value, iter.first);
+ }
+ }
+
+ arrow::util::optional<ValueCacheObject<Value>> get(const Key& key) {
+ // lookup value in the cache
+ typename map_type::iterator value_for_key = map_.find(key);
+ if (value_for_key == map_.end()) {
+ // value not in cache
+ return arrow::util::nullopt;
+ }
+ PriorityItem item = *value_for_key->second.second;
+ // if the value was found on the cache, update its cost (original + inflation)
+ if (item.actual_priority != item.original_priority + this->inflation_cost_) {
+ priority_set_.erase(value_for_key->second.second);
+ auto iter = priority_set_.insert(
+ PriorityItem(item.original_priority + this->inflation_cost_,
+ item.original_priority, item.cache_key));
+ value_for_key->second.second = iter.first;
+ }
+ return value_for_key->second.first;
+ }
+
+ void clear() {
+ map_.clear();
+ priority_set_.clear();
+ }
+
+ private:
+ void evict() {
+ // evict item from the beginning of the set. This set is ordered from the
+ // lower priority value to the higher priority value.
+ typename std::set<PriorityItem>::iterator i = priority_set_.begin();
+ // update the inflation cost related to the evicted item
+ this->inflation_cost_ = (*i).actual_priority;
+ map_.erase((*i).cache_key);
+ priority_set_.erase(i);
+ }
+
+ private:
Review comment:
private specifier not required here
##########
File path: cpp/src/gandiva/greedy_dual_size_cache.h
##########
@@ -0,0 +1,150 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <queue>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+
+// modified cache to support evict policy using the GreedyDual-Size algorithm.
+namespace gandiva {
+// Defines a base value object supported on the cache that may contain properties
+template <typename ValueType>
+class ValueCacheObject {
+ public:
+ explicit ValueCacheObject(ValueType module, uint64_t cost)
+ : module(module), cost(cost) {}
+ ValueCacheObject() = default;
+ ValueType module;
+ uint64_t cost;
+ bool operator<(const ValueCacheObject& other) const { return this->cost < other.cost; }
+};
+
+// a particular LRU based cache which evicts the least recently used item
+// considering the different costs for each entry.
Review comment:
Can you also add comment detailing how the algorithm works? Also include that in the PR description.
##########
File path: cpp/src/gandiva/projector.cc
##########
@@ -186,7 +192,10 @@ Status Projector::Make(SchemaPtr schema, const ExpressionVector& exprs,
// Instantiate the projector with the completely built llvm generator
*projector = std::shared_ptr<Projector>(
new Projector(std::move(llvm_gen), schema, output_fields, configuration));
- cache.PutModule(cache_key, *projector);
+ ValueCacheObject<std::shared_ptr<Projector>> value_cache =
+ *std::make_unique<ValueCacheObject<std::shared_ptr<Projector>>>(*projector,
Review comment:
This is not correct. You are creating a temporary shared pointer and then immediately dereferencing it, which will lead to destructor getting called after the statement.
And why the need to unnecessarily create a temporary shared pointer? just do normal stack initialization.
##########
File path: cpp/src/gandiva/greedy_dual_size_cache.h
##########
@@ -0,0 +1,150 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <queue>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+
+// modified cache to support evict policy using the GreedyDual-Size algorithm.
+namespace gandiva {
+// Defines a base value object supported on the cache that may contain properties
+template <typename ValueType>
+class ValueCacheObject {
+ public:
+ explicit ValueCacheObject(ValueType module, uint64_t cost)
Review comment:
explicit is only required for a single argument constructor.
The below default constructor is also not required
##########
File path: cpp/src/gandiva/greedy_dual_size_cache.h
##########
@@ -0,0 +1,150 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#pragma once
+
+#include <list>
+#include <queue>
+#include <set>
+#include <unordered_map>
+#include <utility>
+
+#include "arrow/util/optional.h"
+
+// modified cache to support evict policy using the GreedyDual-Size algorithm.
+namespace gandiva {
+// Defines a base value object supported on the cache that may contain properties
+template <typename ValueType>
+class ValueCacheObject {
+ public:
+ explicit ValueCacheObject(ValueType module, uint64_t cost)
+ : module(module), cost(cost) {}
+ ValueCacheObject() = default;
+ ValueType module;
+ uint64_t cost;
+ bool operator<(const ValueCacheObject& other) const { return this->cost < other.cost; }
+};
+
+// a particular LRU based cache which evicts the least recently used item
+// considering the different costs for each entry.
+template <class Key, class Value>
+class GreedyDualSizeCache {
+ // inner class to define the priority item
+ class PriorityItem {
+ public:
+ PriorityItem(uint64_t actual_priority, uint64_t original_priority, Key key)
+ : actual_priority(actual_priority),
+ original_priority(original_priority),
+ cache_key(key) {}
+ // this ensure that the items with low priority stays in the beginning of the queue,
+ // so it can be the one removed by evict operation
+ bool operator<(const PriorityItem& other) const {
+ return this->actual_priority < other.actual_priority;
+ }
+ uint64_t actual_priority;
+ uint64_t original_priority;
+ Key cache_key;
+ };
+
+ public:
+ struct hasher {
+ template <typename I>
+ std::size_t operator()(const I& i) const {
+ return i.Hash();
+ }
+ };
+ // a map from 'key' to a pair of Value and a pointer to the priority value
+ using map_type = std::unordered_map<
+ Key, std::pair<ValueCacheObject<Value>, typename std::set<PriorityItem>::iterator>,
+ hasher>;
+
+ explicit GreedyDualSizeCache(size_t capacity) : cache_capacity_(capacity) {
+ this->inflation_cost_ = 0;
+ }
+
+ GreedyDualSizeCache<Key, Value>() : cache_capacity_(capacity) {}
+
+ ~GreedyDualSizeCache() = default;
+
+ size_t size() const { return map_.size(); }
+
+ size_t capacity() const { return this->cache_capacity_; }
+
+ bool empty() const { return map_.empty(); }
+
+ bool contains(const Key& key) { return map_.find(key) != map_.end(); }
+
+ void insert(const Key& key, const ValueCacheObject<Value>& value) {
+ typename map_type::iterator i = map_.find(key);
+ // check if element is not in the cache to add it
+ if (i == map_.end()) {
+ // insert item into the cache, but first check if it is full, to evict an item
+ // if it is necessary
+ if (size() >= this->cache_capacity_) {
+ evict();
+ }
+
+ // insert the new item
+ auto iter = this->priority_set_.insert(
+ PriorityItem(value.cost + this->inflation_cost_, value.cost, key));
+ // save on map the value and the priority item iterator position
+ map_[key] = std::make_pair(value, iter.first);
+ }
+ }
+
+ arrow::util::optional<ValueCacheObject<Value>> get(const Key& key) {
+ // lookup value in the cache
+ typename map_type::iterator value_for_key = map_.find(key);
+ if (value_for_key == map_.end()) {
+ // value not in cache
+ return arrow::util::nullopt;
+ }
+ PriorityItem item = *value_for_key->second.second;
+ // if the value was found on the cache, update its cost (original + inflation)
+ if (item.actual_priority != item.original_priority + this->inflation_cost_) {
+ priority_set_.erase(value_for_key->second.second);
+ auto iter = priority_set_.insert(
+ PriorityItem(item.original_priority + this->inflation_cost_,
+ item.original_priority, item.cache_key));
+ value_for_key->second.second = iter.first;
+ }
+ return value_for_key->second.first;
+ }
+
+ void clear() {
+ map_.clear();
+ priority_set_.clear();
+ }
+
+ private:
+ void evict() {
+ // evict item from the beginning of the set. This set is ordered from the
+ // lower priority value to the higher priority value.
+ typename std::set<PriorityItem>::iterator i = priority_set_.begin();
+ // update the inflation cost related to the evicted item
+ this->inflation_cost_ = (*i).actual_priority;
+ map_.erase((*i).cache_key);
+ priority_set_.erase(i);
+ }
+
+ private:
+ map_type map_;
+ std::set<PriorityItem> priority_set_;
+ int64_t inflation_cost_;
Review comment:
uint64_t? (same as priority cost)
Also since the inflation_cost is always increasing, is there a possibility of overflow?
##########
File path: cpp/src/gandiva/cache.h
##########
@@ -34,26 +35,29 @@ void LogCacheSize(size_t capacity);
template <class KeyType, typename ValueType>
class Cache {
public:
- explicit Cache(size_t capacity) : cache_(capacity) { LogCacheSize(capacity); }
+ explicit Cache(size_t capacity) {
+ this->cache_ = std::make_unique<GreedyDualSizeCache<KeyType, ValueType>>(capacity);
+ LogCacheSize(capacity);
+ }
Cache() : Cache(GetCapacity()) {}
ValueType GetModule(KeyType cache_key) {
- arrow::util::optional<ValueType> result;
+ arrow::util::optional<ValueCacheObject<ValueType>> result;
mtx_.lock();
- result = cache_.get(cache_key);
+ result = (*cache_).get(cache_key);
mtx_.unlock();
- return result != arrow::util::nullopt ? *result : nullptr;
+ return result != arrow::util::nullopt ? (*result).module : nullptr;
}
- void PutModule(KeyType cache_key, ValueType module) {
+ void PutModule(KeyType cache_key, ValueCacheObject<ValueType> valueCacheObject) {
mtx_.lock();
- cache_.insert(cache_key, module);
+ (*cache_).insert(cache_key, valueCacheObject);
mtx_.unlock();
}
private:
- LruCache<KeyType, ValueType> cache_;
+ std::unique_ptr<GreedyDualSizeCache<KeyType, ValueType>> cache_;
Review comment:
why not just keep the object instead of pointer like in earlier code?
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