1543d5d92e
Summary: It is hard to measure acutal memory usage by std containers. Even providing a custom allocator will miss count some of the usage. Here we only do a wild guess on its memory usage. Closes https://github.com/facebook/rocksdb/pull/1511 Differential Revision: D4179945 Pulled By: yiwu-arbug fbshipit-source-id: 32ab929
26 lines
882 B
C++
26 lines
882 B
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once
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#include <unordered_map>
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namespace rocksdb {
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// Helper methods to estimate memroy usage by std containers.
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template <class Key, class Value, class Hash>
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size_t ApproximateMemoryUsage(
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const std::unordered_map<Key, Value, Hash>& umap) {
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typedef std::unordered_map<Key, Value, Hash> Map;
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return sizeof(umap) +
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// Size of all items plus a next pointer for each item.
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(sizeof(typename Map::value_type) + sizeof(void*)) * umap.size() +
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// Size of hash buckets.
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umap.bucket_count() * sizeof(void*);
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}
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} // namespace rocksdb
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