src/common/Thread.cpp

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#include "Thread.h"

Thread::Thread(bool RealTime, int PriorityMax, int PriorityDelta) {
    this->isRealTime        = RealTime;
    this->Running           = false;
    this->PriorityDelta     = PriorityDelta;
    this->PriorityMax       = PriorityMax;
    __thread_destructor_key = 0;
    pthread_mutex_init(&__thread_state_mutex, NULL);
    pthread_cond_init(&__thread_start_condition, NULL);
    pthread_cond_init(&__thread_exit_condition, NULL);
}

Thread::~Thread() {
    StopThread();
    pthread_cond_destroy(&__thread_start_condition);
    pthread_cond_destroy(&__thread_exit_condition);
    pthread_mutex_destroy(&__thread_state_mutex);
}

/**
 *  Starts the thread. This method will wait until the thread actually
 *  started it's execution before it will return. The abstract method
 *  Main() is the entry point for the new thread. You have to implement the
 *  Main() method in your subclass.
 */
int Thread::StartThread() {
    pthread_mutex_lock(&__thread_state_mutex);
    if (!Running) {
        SignalStartThread();
        pthread_cond_wait(&__thread_start_condition, &__thread_state_mutex);
    }
    pthread_mutex_unlock(&__thread_state_mutex);
    return 0;
}

/**
 *  Starts the thread. This method will signal to start the thread and
 *  return immediately. Note that the thread might not yet run when this
 *  method returns! The abstract method Main() is the entry point for the
 *  new thread. You have to implement the Main() method in your subclass.
 *
 *  @see StartThread()
 */
int Thread::SignalStartThread() {
    // Create and run the thread
    int res = pthread_create(&this->__thread_id, NULL, __pthread_launcher, this);
    switch (res) {
        case 0: // Success
            break;
        case EAGAIN:
            std::cerr << "Thread creation failed: System doesn't allow to create another thread."
                      << std::endl << std::flush;
            this->Running = false;
            break;
        case EPERM:
            std::cerr << "Thread creation failed: You're lacking permisssions to set required scheduling policy and parameters."
                      << std::endl << std::flush;
            this->Running = false;
            break;
        default:
            std::cerr << "Thread creation failed: Unknown cause."
                      << std::endl << std::flush;
            this->Running = false;
            break;
    }
    return res;
}

/**
 *  Stops the thread. This method will wait until the thread actually stopped
 *  it's execution before it will return.
 */
int Thread::StopThread() {
    pthread_mutex_lock(&__thread_state_mutex);
    if (Running) {
        SignalStopThread();
        pthread_cond_wait(&__thread_exit_condition, &__thread_state_mutex);
    }
    pthread_mutex_unlock(&__thread_state_mutex);
    return 0;
}

/**
 *  Stops the thread. This method will signal to stop the thread and return
 *  immediately. Note that the thread might still run when this method
 *  returns!
 *
 *  @see StopThread()
 */
int Thread::SignalStopThread() {
    pthread_cancel(__thread_id);
    return 0;
}

/**
 *  Sets the process SCHED_FIFO policy,  if max=1 then set at max priority,
 *  else use min priority. delta is added to the priority so that we can
 *  for example set 3 SCHED_FIFO tasks to different priorities by specifying
 *  delta  0 , -1 , -2  ( 0 = highest priority because -1 is subtracted to the
 *  current priority).
 */
int Thread::SetSchedulingPriority() {
    struct sched_param schp;

    if (!isRealTime) return 0;

    if (mlockall(MCL_CURRENT | MCL_FUTURE) < 0) {
        perror("WARNING, can't mlockall() memory!");
    }

    /*
     * set the process to realtime privs
     */
    memset(&schp, 0, sizeof(schp));
    if (this->PriorityMax == 1) {
        schp.sched_priority = sched_get_priority_max(SCHED_FIFO) + this->PriorityDelta;
    }
    if (this->PriorityMax == -1) {
        schp.sched_priority = sched_get_priority_min(SCHED_FIFO) + this->PriorityDelta;
    }

    if (sched_setscheduler(0, SCHED_FIFO, &schp) != 0) {
        perror("sched_setscheduler");
        return -1;
    }

    return 0;
}

/**
 *  Registers thread destructor callback function which will be executed when
 *  the thread stops it's execution and sets the 'Running' flag to true. This
 *  method will be called by the __pthread_launcher callback function, DO NOT
 *  CALL THIS METHOD YOURSELF!
 */
void Thread::EnableDestructor() {
    pthread_mutex_lock(&__thread_state_mutex);
    pthread_key_create(&__thread_destructor_key, __pthread_destructor);
    pthread_setspecific(__thread_destructor_key, this);
    Running = true;
    pthread_mutex_unlock(&__thread_state_mutex);
    pthread_cond_broadcast(&__thread_start_condition);
}

/**
 *  Will be called by the kernel when the thread stops it's execution.
 */
int Thread::Destructor() {
    pthread_key_delete(__thread_destructor_key);
    pthread_mutex_lock(&__thread_state_mutex);
    Running = false;
    pthread_mutex_unlock(&__thread_state_mutex);
    pthread_cond_broadcast(&__thread_exit_condition);
}

/// Callback function for the POSIX thread API
void* __pthread_launcher(void* thread) {
    Thread* t;
    t = (Thread*) thread;
    t->SetSchedulingPriority();
    t->EnableDestructor();
    t->Main();
}

/// Callback function for the POSIX thread API
void __pthread_destructor(void* thread) {
    Thread* t;
    t = (Thread*) thread;
    t->Destructor();
}
1	schoenebeck	53	/***************************************************************************
2			* *
3			* LinuxSampler - modular, streaming capable sampler *
4			* *
5	schoenebeck	56	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	schoenebeck	53	* *
7			* This program is free software; you can redistribute it and/or modify *
8			* it under the terms of the GNU General Public License as published by *
9			* the Free Software Foundation; either version 2 of the License, or *
10			* (at your option) any later version. *
11			* *
12			* This program is distributed in the hope that it will be useful, *
13			* but WITHOUT ANY WARRANTY; without even the implied warranty of *
14			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
15			* GNU General Public License for more details. *
16			* *
17			* You should have received a copy of the GNU General Public License *
18			* along with this program; if not, write to the Free Software *
19			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
20			* MA 02111-1307 USA *
21			***************************************************************************/
22
23			#include "Thread.h"
24
25			Thread::Thread(bool RealTime, int PriorityMax, int PriorityDelta) {
26			this->isRealTime = RealTime;
27			this->Running = false;
28			this->PriorityDelta = PriorityDelta;
29			this->PriorityMax = PriorityMax;
30			__thread_destructor_key = 0;
31			pthread_mutex_init(&__thread_state_mutex, NULL);
32	schoenebeck	57	pthread_cond_init(&__thread_start_condition, NULL);
33	schoenebeck	53	pthread_cond_init(&__thread_exit_condition, NULL);
34			}
35
36			Thread::~Thread() {
37	schoenebeck	57	StopThread();
38			pthread_cond_destroy(&__thread_start_condition);
39	schoenebeck	53	pthread_cond_destroy(&__thread_exit_condition);
40			pthread_mutex_destroy(&__thread_state_mutex);
41			}
42
43			/**
44	schoenebeck	57	* Starts the thread. This method will wait until the thread actually
45			* started it's execution before it will return. The abstract method
46			* Main() is the entry point for the new thread. You have to implement the
47			* Main() method in your subclass.
48	schoenebeck	53	*/
49			int Thread::StartThread() {
50	schoenebeck	57	pthread_mutex_lock(&__thread_state_mutex);
51			if (!Running) {
52			SignalStartThread();
53			pthread_cond_wait(&__thread_start_condition, &__thread_state_mutex);
54			}
55			pthread_mutex_unlock(&__thread_state_mutex);
56			return 0;
57			}
58
59			/**
60			* Starts the thread. This method will signal to start the thread and
61			* return immediately. Note that the thread might not yet run when this
62			* method returns! The abstract method Main() is the entry point for the
63			* new thread. You have to implement the Main() method in your subclass.
64			*
65			* @see StartThread()
66			*/
67			int Thread::SignalStartThread() {
68	schoenebeck	53	// Create and run the thread
69			int res = pthread_create(&this->__thread_id, NULL, __pthread_launcher, this);
70			switch (res) {
71			case 0: // Success
72			break;
73			case EAGAIN:
74			std::cerr << "Thread creation failed: System doesn't allow to create another thread."
75			<< std::endl << std::flush;
76			this->Running = false;
77			break;
78			case EPERM:
79			std::cerr << "Thread creation failed: You're lacking permisssions to set required scheduling policy and parameters."
80			<< std::endl << std::flush;
81			this->Running = false;
82			break;
83			default:
84			std::cerr << "Thread creation failed: Unknown cause."
85			<< std::endl << std::flush;
86			this->Running = false;
87			break;
88			}
89			return res;
90			}
91
92			/**
93			* Stops the thread. This method will wait until the thread actually stopped
94			* it's execution before it will return.
95			*/
96			int Thread::StopThread() {
97			pthread_mutex_lock(&__thread_state_mutex);
98			if (Running) {
99			SignalStopThread();
100			pthread_cond_wait(&__thread_exit_condition, &__thread_state_mutex);
101			}
102			pthread_mutex_unlock(&__thread_state_mutex);
103			return 0;
104			}
105
106			/**
107			* Stops the thread. This method will signal to stop the thread and return
108			* immediately. Note that the thread might still run when this method
109			* returns!
110	schoenebeck	57	*
111			* @see StopThread()
112	schoenebeck	53	*/
113			int Thread::SignalStopThread() {
114			pthread_cancel(__thread_id);
115			return 0;
116			}
117
118			/**
119			* Sets the process SCHED_FIFO policy, if max=1 then set at max priority,
120			* else use min priority. delta is added to the priority so that we can
121			* for example set 3 SCHED_FIFO tasks to different priorities by specifying
122			* delta 0 , -1 , -2 ( 0 = highest priority because -1 is subtracted to the
123			* current priority).
124			*/
125			int Thread::SetSchedulingPriority() {
126			struct sched_param schp;
127
128	schoenebeck	57	if (!isRealTime) return 0;
129
130	schoenebeck	53	if (mlockall(MCL_CURRENT \| MCL_FUTURE) < 0) {
131			perror("WARNING, can't mlockall() memory!");
132			}
133
134			/*
135			* set the process to realtime privs
136			*/
137			memset(&schp, 0, sizeof(schp));
138			if (this->PriorityMax == 1) {
139			schp.sched_priority = sched_get_priority_max(SCHED_FIFO) + this->PriorityDelta;
140			}
141			if (this->PriorityMax == -1) {
142			schp.sched_priority = sched_get_priority_min(SCHED_FIFO) + this->PriorityDelta;
143			}
144
145			if (sched_setscheduler(0, SCHED_FIFO, &schp) != 0) {
146			perror("sched_setscheduler");
147			return -1;
148			}
149
150			return 0;
151			}
152
153			/**
154			* Registers thread destructor callback function which will be executed when
155			* the thread stops it's execution and sets the 'Running' flag to true. This
156			* method will be called by the __pthread_launcher callback function, DO NOT
157			* CALL THIS METHOD YOURSELF!
158			*/
159			void Thread::EnableDestructor() {
160			pthread_mutex_lock(&__thread_state_mutex);
161			pthread_key_create(&__thread_destructor_key, __pthread_destructor);
162			pthread_setspecific(__thread_destructor_key, this);
163			Running = true;
164			pthread_mutex_unlock(&__thread_state_mutex);
165	schoenebeck	57	pthread_cond_broadcast(&__thread_start_condition);
166	schoenebeck	53	}
167
168			/**
169			* Will be called by the kernel when the thread stops it's execution.
170			*/
171			int Thread::Destructor() {
172			pthread_key_delete(__thread_destructor_key);
173			pthread_mutex_lock(&__thread_state_mutex);
174			Running = false;
175			pthread_mutex_unlock(&__thread_state_mutex);
176			pthread_cond_broadcast(&__thread_exit_condition);
177			}
178
179			/// Callback function for the POSIX thread API
180			void* __pthread_launcher(void* thread) {
181			Thread* t;
182			t = (Thread*) thread;
183	schoenebeck	57	t->SetSchedulingPriority();
184	schoenebeck	53	t->EnableDestructor();
185			t->Main();
186			}
187
188			/// Callback function for the POSIX thread API
189			void __pthread_destructor(void* thread) {
190			Thread* t;
191			t = (Thread*) thread;
192			t->Destructor();
193			}