6cc9aef162
Summary: Previously users could set `max_background_flushes=0` to force rocksdb to use a single thread pool for both background flushes and compactions. That'll no longer be possible since I'm going to deprecate `max_background_flushes` and `max_background_compactions` in favor of a single option. This diff introduces a new way to force a single thread pool: when high-pri pool has zero threads, all background jobs will be submitted to low-pri pool. Note the majority of the code change is adding `Env::GetBackgroundThreads()`, which is necessary to check whether the user has provided a zero-sized thread pool. Closes https://github.com/facebook/rocksdb/pull/2204 Differential Revision: D4936256 Pulled By: ajkr fbshipit-source-id: 929a07a0c0705f7766f5339cd013ff74e90d6e01
112 lines
3.7 KiB
C++
112 lines
3.7 KiB
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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// This source code is also licensed under the GPLv2 license found in the
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// COPYING file in the root directory of this source tree.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "rocksdb/threadpool.h"
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#include "rocksdb/env.h"
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#include <memory>
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#include <functional>
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namespace rocksdb {
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class ThreadPoolImpl : public ThreadPool {
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public:
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ThreadPoolImpl();
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~ThreadPoolImpl();
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ThreadPoolImpl(ThreadPoolImpl&&) = delete;
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ThreadPoolImpl& operator=(ThreadPoolImpl&&) = delete;
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// Implement ThreadPool interfaces
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// Wait for all threads to finish.
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// Discards all the the jobs that did not
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// start executing and waits for those running
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// to complete
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void JoinAllThreads() override;
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// Set the number of background threads that will be executing the
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// scheduled jobs.
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void SetBackgroundThreads(int num) override;
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int GetBackgroundThreads() override;
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// Get the number of jobs scheduled in the ThreadPool queue.
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unsigned int GetQueueLen() const override;
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// Waits for all jobs to complete those
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// that already started running and those that did not
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// start yet
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void WaitForJobsAndJoinAllThreads() override;
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// Make threads to run at a lower kernel priority
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// Currently only has effect on Linux
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void LowerIOPriority();
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// Ensure there is at aleast num threads in the pool
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// but do not kill threads if there are more
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void IncBackgroundThreadsIfNeeded(int num);
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// Submit a fire and forget job
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// These jobs can not be unscheduled
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// This allows to submit the same job multiple times
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void SubmitJob(const std::function<void()>&) override;
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// This moves the function in for efficiency
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void SubmitJob(std::function<void()>&&) override;
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// Schedule a job with an unschedule tag and unschedule function
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// Can be used to filter and unschedule jobs by a tag
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// that are still in the queue and did not start running
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void Schedule(void (*function)(void* arg1), void* arg, void* tag,
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void (*unschedFunction)(void* arg));
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// Filter jobs that are still in a queue and match
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// the given tag. Remove them from a queue if any
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// and for each such job execute an unschedule function
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// if such was given at scheduling time.
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int UnSchedule(void* tag);
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void SetHostEnv(Env* env);
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Env* GetHostEnv() const;
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// Return the thread priority.
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// This would allow its member-thread to know its priority.
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Env::Priority GetThreadPriority() const;
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// Set the thread priority.
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void SetThreadPriority(Env::Priority priority);
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static void PthreadCall(const char* label, int result);
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struct Impl;
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private:
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// Current public virtual interface does not provide usable
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// functionality and thus can not be used internally to
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// facade different implementations.
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//
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// We propose a pimpl idiom in order to easily replace the thread pool impl
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// w/o touching the header file but providing a different .cc potentially
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// CMake option driven.
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//
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// Another option is to introduce a Env::MakeThreadPool() virtual interface
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// and override the environment. This would require refactoring ThreadPool usage.
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//
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// We can also combine these two approaches
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std::unique_ptr<Impl> impl_;
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};
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} // namespace rocksdb
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