aya/engine/core/src/TaskScheduler.hpp

#pragma once
#include <set>
#include <vector>

#include "RunningAverage.hpp"
#include "Declarations.hpp"
#include "Debug.hpp"
#include "threadsafe.hpp"
#include "boost.hpp"
#include "CEvent.hpp"
#include "atomic.hpp"

#include "boost/thread.hpp"
#include "boost/function.hpp"
#include "boost/shared_ptr.hpp"
#include "boost/scoped_ptr.hpp"
#include "boost/noncopyable.hpp"
#include "boost/intrusive/list.hpp"

#ifdef _WIN32
#undef min
#undef max
#endif


LOGGROUP(TaskSchedulerInit)
LOGGROUP(TaskSchedulerRun)
LOGGROUP(TaskSchedulerFindJob)

namespace Aya
{
/// A singleton object responsible for scheduling the execution TaskScheduler.Jobs.
class TaskScheduler
{
    struct SleepingTag;
    typedef boost::intrusive::list_base_hook<boost::intrusive::tag<SleepingTag>> SleepingHook;
    struct WaitingTag;
    typedef boost::intrusive::list_base_hook<boost::intrusive::tag<WaitingTag>> WaitingHook;

public:
    class Thread;
    typedef std::vector<boost::shared_ptr<Thread>> Threads;
    class Job;
    bool DataModel30fpsThrottle;
    Time lastCyclcTimestamp;
    bool cyclicExecutiveWaitForNextFrame;
    int nonCyclicJobsToDo;
    int cyclicExecutiveLoopId;
    class AyaBaseClass Arbiter
    {
    protected:
        ActivityMeter<2> activityMeter;

    public:
        virtual std::string arbiterName() = 0;
        virtual bool areExclusive(Job* job1, Job* job2) = 0;
        virtual bool isThrottled() = 0;
        virtual void preStep(TaskScheduler::Job* job)
        {
            activityMeter.increment();
        }
        virtual void postStep(TaskScheduler::Job* job)
        {
            activityMeter.decrement();
        }
        double getAverageActivity()
        {
            return activityMeter.averageValue();
        }
        virtual Arbiter* getSyncronizationArbiter()
        {
            return this;
        };
        virtual int getNumPlayers() const
        {
            return 1;
        }
    };

    typedef enum
    {
        Done,    // The job will be removed from the TaskScheduler
        Stepped, // Another step will be scheduled
    } StepResult;

    static TaskScheduler& singleton();

    typedef enum
    {
        LastError,
        AccumulatedError,
        FIFO
    } PriorityMethod;
    static PriorityMethod priorityMethod;

#ifdef AYA_TEST_BUILD
    static int findJobFPS;
    static bool updateJobPriorityOnWake;
#endif
    double threadAffinityPreference;
    typedef enum
    {
        PerCore4 = 104,
        PerCore3 = 103,
        PerCore2 = 102,
        PerCore1 = 101,
        Auto = 0,
        Threads1 = 1,
        Threads2 = 2,
        Threads3 = 3,
        Threads4 = 4,
        Threads8 = 8,
        Threads16 = 16
    } ThreadPoolConfig;

    bool shouldDropThread() const;
    void dropThread(Thread* thread);

    size_t getThreadCount()
    {
        return threadCount;
    }
    void setThreadCount(ThreadPoolConfig threadConfig);
    void disableThreads(int count, Threads& threads);
    void enableThreads(Threads& threads);

    void add(boost::shared_ptr<TaskScheduler::Job> job);
    void reschedule(boost::shared_ptr<TaskScheduler::Job> job);

    void remove(boost::shared_ptr<TaskScheduler::Job> job)
    {
        remove(job, false, NULL);
    }
    // This version of remove might lead to deadlocks in some cases, so try not to use it
    void removeBlocking(boost::shared_ptr<TaskScheduler::Job> job)
    {
        remove(job, true, NULL);
    }
    // This version of remove calls back several times a second while waiting.
    // You might use this to process events in order to avoid deadlocks.
    void removeBlocking(boost::shared_ptr<TaskScheduler::Job> job, boost::function<void()> callbackPing)
    {
        remove(job, true, callbackPing);
    }

    void getJobsInfo(std::vector<boost::shared_ptr<const Job>>& result);
    void getJobsByName(const std::string& name, std::vector<boost::shared_ptr<const Job>>& result);

    // Performance counters
    double numSleepingJobs() const
    {
        return sleepingJobCount.value();
    }
    double numWaitingJobs() const
    {
        return waitingJobCount.value();
    }
    double numRunningJobs() const
    {
        return averageRunningJobCount.value();
    }
    double threadAffinity() const
    {
        return averageThreadAffinity.value();
    }
    size_t threadPoolSize() const
    {
        return threads.size();
    }
    double schedulerRate() const
    {
        return schedulerDutyCycle.rate();
    }
    double getSchedulerDutyCyclePerThread() const;
    double getErrorCalculationRate() const
    {
        return errorCalculationPerSec.rate();
    }
    double getSortFrequency() const
    {
        return sortFrequency.rate();
    }
    Aya::atomic<int> taskCount;
    void printDiagnostics(bool aggregateJobs);
    void printJobs();
    void setJobsExtendedStatsWindow(double seconds); // set seconds to 0.0 to disable.
    void cancelCyclicExecutive();
    bool isCyclicExecutive()
    {
        return cyclicExecutiveEnabled;
    }
    void releaseCyclicExecutive(TaskScheduler::Job* job);

private:
    // ** Here for thread saftey.  **
    struct CyclicExecutiveJob
    {
        boost::shared_ptr<TaskScheduler::Job> job;
        bool cyclicExecutiveExecuted;
        bool isRunning;

        CyclicExecutiveJob(const boost::shared_ptr<TaskScheduler::Job>& j)
        {
            job = j;
            cyclicExecutiveExecuted = false;
            isRunning = false;
        }

        // Allows for using std::find.
        bool operator==(const boost::shared_ptr<TaskScheduler::Job>& j)
        {
            return job == j;
        }
        bool operator==(const TaskScheduler::Job& j)
        {
            return job.get() == &j;
        }
    };

    TaskScheduler();
    ~TaskScheduler();
    void endAllThreads();
    void sampleRunningJobCount();

    static bool jobCompare(const CyclicExecutiveJob& jobA, const CyclicExecutiveJob& jobB);

    void remove(boost::shared_ptr<TaskScheduler::Job> job, bool joinJob, boost::function<void()> callbackPing);
    void remove(const boost::shared_ptr<TaskScheduler::Job>& job, boost::shared_ptr<CEvent> joinEvent);

    void scheduleJob(Job& job);

    static bool areExclusive(Job* job1, Job* job2, const shared_ptr<Arbiter>& arbiterHint);
    bool conflictsWithScheduledJob(Job* item) const;

    void incrementThreadCount();
    void decrementThreadCount();

    Aya::mutex mutex;

    typedef std::set<shared_ptr<Job>> AllJobs;
    AllJobs allJobs;
    typedef boost::intrusive::list<Job, boost::intrusive::base_hook<SleepingHook>> SleepingJobs;
    SleepingJobs sleepingJobs;
    bool cyclicExecutiveEnabled;
    typedef std::vector<CyclicExecutiveJob> CyclicExecutiveJobs;
    CyclicExecutiveJobs cyclicExecutiveJobs;
    typedef boost::intrusive::list<Job, boost::intrusive::base_hook<WaitingHook>> WaitingJobs;
    WaitingJobs waitingJobs;

    shared_ptr<Job> nextScheduledJob;

    void wakeSleepingJobs();
    void enqueueWaitingJob(Job& job);
    Time::Interval getShortestSleepTime() const;
    boost::shared_ptr<Job> findJobToRun(boost::shared_ptr<Thread> requestingThread);
    boost::shared_ptr<Job> findJobToRunNonCyclicJobs(boost::shared_ptr<Thread> requestingThread, Aya::Time now);
    int numNonCyclicJobsWithWork();

    void checkStillWaitingNextFrame(Time now);

    RunningAverage<int> sleepingJobCount;
    RunningAverage<int> waitingJobCount;
    RunningAverage<int> averageRunningJobCount;
    RunningAverageDutyCycle<Time::Precise> schedulerDutyCycle; // time spent scheduling jobs
    RunningAverage<double> averageThreadAffinity;
    RunningAverageTimeInterval<> errorCalculationPerSec;
    RunningAverageTimeInterval<> sortFrequency;

    Aya::atomic<int> runningJobCount;

    Time nextWakeTime;

    Time lastSortTime;

    Threads threads;
    size_t desiredThreadCount;

    CEvent sampleRunningJobCountEvent;
    boost::scoped_ptr<boost::thread> runningJobCounterThread;

    Aya::atomic<int> threadCount;

    static Aya::thread_specific_reference<TaskScheduler::Job> currentJob;
    static void static_init();
};


// A simple arbiter that prevents all members of it to execute concurrently
class ExclusiveArbiter
    : public TaskScheduler::Arbiter
    , boost::noncopyable
{
public:
    virtual bool areExclusive(TaskScheduler::Job* job1, TaskScheduler::Job* job2);
    virtual std::string arbiterName()
    {
        return "ExclusiveArbiter";
    }
    virtual bool isThrottled()
    {
        return false;
    }
    static ExclusiveArbiter singleton;
};



class SimpleThrottlingArbiter : public TaskScheduler::Arbiter
{
    mutable bool throttled;
    Aya::atomic<int> updatingThrottle;
    static Aya::atomic<int> arbiterCount;

public:
    static bool isThrottlingEnabled;

    SimpleThrottlingArbiter()
        : throttled(false)
        , updatingThrottle(0)
    {
        ++arbiterCount;
    }

    ~SimpleThrottlingArbiter()
    {
        --arbiterCount;
    }

    virtual bool isThrottled()
    {
        if (!isThrottlingEnabled)
            return false;

        long count = arbiterCount;
        if (count <= 1)
            return false;
        if (updatingThrottle.swap(1) == 0)
        {
            double cutoff = ((double)Aya::TaskScheduler::singleton().getThreadCount()) / (double)count;
            // hysteresis
            if (throttled)
            {
                throttled = getAverageActivity() >= cutoff;
            }
            else
            {
                throttled = getAverageActivity() >= 1.1 * cutoff;
            }

            --updatingThrottle;
        }

        return throttled;
    }
};


} // namespace Aya