Process.h

Go to the documentation of this file.

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_SYSTEM_PROCESS_H
#define META_OCEAN_SYSTEM_PROCESS_H
 
#include "ocean/system/System.h"
 
#include "ocean/base/Singleton.h"
 
namespace Ocean
{
 
namespace System
{
 
/**
 * This class implements basic functions related with the application process.
 * @ingroup system
 */
class OCEAN_SYSTEM_EXPORT Process : public Singleton<Process>
{
    friend class Singleton<Process>;
 
    public:
 
        /**
         * Definition of different process priority values.
         */
        enum ProcessPriority
        {
            /// The process runs if the system is idle.
            PRIORITY_IDLE,
            /// The process has a priority below normal.
            PRIORITY_BELOW_NORMAL,
            /// The process has a normal priority.
            PRIORITY_NORMAL,
            /// The process has a priority above normal.
            PRIORITY_ABOVE_NORMAL,
            /// The process has a high priority.
            PRIORITY_HIGH,
            /// The process has a realtime priority.
            PRIORITY_REALTIME
        };
 
    public:
 
        /**
         * Returns the processor load since the last call to this function.
         * @return Current processor load in percent, with range [0.0, 1.0]
         */
        float currentProcessorLoad() const;
 
        /**
         * Returns the average processor load of this process since the creation.
         * @return Average processor load in percent, with range [0.0, 1.0]
         */
        float averageProcessorLoad() const;
 
        /**
         * Returns the entire processor time of this process since the creation.
         * @return Entire processor time in seconds
         */
        static double entireProcessorTime();
 
        /**
         * Returns the live time of this process since the creation.
         * @return Live time in seconds
         */
        static double entireProcessLiveTime();
 
        /**
         * Returns the start time of this process since 01.01.1970 00:00:00 in UTC time.
         * @return Start time in microseconds
         */
        static long long processStartTime();
 
        /**
         * Returns the priority of the process.
         * @return Process priority
         * @exception NotSupportedException Is thrown if this function is not supported
         */
        static ProcessPriority priority();
 
        /**
         * Sets the priority of the process.
         * @param priority Process priority to set
         * @return True, if succeeded
         */
        static bool setPriority(const ProcessPriority priority);
 
        /**
         * Returns the process id of the current (calling) process.
         * @return The process id of the current process
         */
        static unsigned int currentProcessId();
 
    private:
 
        /**
         * Creates a new process object.
         * As this class is a singleton get access to this object by the singleton.
         */
        Process();
 
    private:
 
        /// Time of most recent processor load request.
        mutable int64_t loadTimestamp_ = 0ll;
 
        /// Processor user time of most recent processor load request.
        mutable int64_t loadTime_ = 0ll;
 
        /// Number of real CPU cores available in this system.
        const unsigned int numberCores_ = 0u;
};
 
}
 
}
 
#endif // META_OCEAN_SYSTEM_PROCESS_H