folly/folly/compression/CompressionCoreLocalContextPool.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed 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 <folly/compression/CompressionContextPool.h>
#include <folly/concurrency/CacheLocality.h>

namespace folly {
namespace compression {

/**
 * This class is intended to reduce contention on reserving a compression
 * context and improve cache locality (but maybe not hotness) of the contexts
 * it manages.
 *
 * This class uses folly::AccessSpreader to spread the managed object across
 * NumStripes domains (which should correspond to a topologically close set of
 * hardware threads). This cache is still backed by the basic locked stack in
 * the folly::compression::CompressionContextPool.
 *
 * Note that there is a tradeoff in choosing the number of stripes. More stripes
 * make for less contention, but mean that a context is less likely to be hot
 * in cache.
 */
template <
    typename T,
    typename Creator,
    typename Deleter,
    typename Resetter,
    size_t NumStripes = 8>
class CompressionCoreLocalContextPool { … };
} // namespace compression
} // namespace folly