brpc/src/bthread/timer_thread.h at master · apache/brpc · GitHub

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// 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.

// bthread - An M:N threading library to make applications more concurrent.

#ifndef BTHREAD_TIMER_THREAD_H

#define BTHREAD_TIMER_THREAD_H

#include <vector> // std::vector

#include <pthread.h> // pthread_*

#include "butil/atomicops.h"

#include "butil/time.h" // time utilities

#include "bthread/mutex.h"

namespace bthread {

struct TimerThreadOptions {

// Scheduling requests are hashed into different bucket to improve

// scalability. However bigger num_buckets may NOT result in more scalable

// schedule() because bigger values also make each buckets more sparse

// and more likely to lock the global mutex. You better not change

// this value, just leave it to us.

// Default: 13

size_t num_buckets;

// If this field is not empty, some bvar for reporting stats of TimerThread

// will be exposed with this prefix.

// Default: ""

std::string bvar_prefix;

// Constructed with default options.

TimerThreadOptions();

};

// TimerThread is a separate thread to run scheduled tasks at specific time.

// At most one task runs at any time, don't put time-consuming code in the

// callback otherwise the task may delay other tasks significantly.

class TimerThread {

public:

struct Task;

class Bucket;

typedef uint64_t TaskId;

const static TaskId INVALID_TASK_ID;

TimerThread();

~TimerThread();

// Start the timer thread.

// This method should only be called once.

// return 0 if success, errno otherwise.

int start(const TimerThreadOptions* options);

// Stop the timer thread. Later schedule() will return INVALID_TASK_ID.

void stop_and_join();

// Schedule |fn(arg)| to run at realtime |abstime| approximately.

// Returns: identifier of the scheduled task, INVALID_TASK_ID on error.

TaskId schedule(void (*fn)(void*), void* arg, const timespec& abstime);

// Prevent the task denoted by `task_id' from running. `task_id' must be

// returned by schedule() ever.

// Returns:

// 0 - Removed the task which does not run yet

// -1 - The task does not exist.

// 1 - The task is just running.

int unschedule(TaskId task_id);

// Get identifier of internal pthread.

// Returns (pthread_t)0 if start() is not called yet.

pthread_t thread_id() const { return _thread; }

private:

// the timer thread will run this method.

void run();

static void* run_this(void* arg);

bool _started; // whether the timer thread was started successfully.

butil::atomic<bool> _stop;

TimerThreadOptions _options;

Bucket* _buckets; // list of tasks to be run

FastPthreadMutex _mutex; // protect _nearest_run_time

int64_t _nearest_run_time;

// the futex for wake up timer thread. can't use _nearest_run_time because

// it's 64-bit.

int _nsignals;

// Number of tasks buffered in the internal min-heap, published by the

// timer thread each iteration. Not part of the public API; read by unit

// tests through the -fno-access-control build flag.

butil::atomic<int64_t> _npending;

pthread_t _thread; // all scheduled task will be run on this thread

};

// Get the global TimerThread which never quits.

TimerThread* get_or_create_global_timer_thread();

TimerThread* get_global_timer_thread();

} // end namespace bthread

#endif // BTHREAD_TIMER_THREAD_H

brpc/src/bthread/timer_thread.h at master · apache/brpc · GitHub

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