source: trunk/libs/pthread.h @ 419

Last change on this file since 419 was 412, checked in by alain, 5 years ago

Introduce user libraries

File size: 14.1 KB
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1/*
2 * pthread.h - User side pthread related library definition.
3 *
4 * Author     Alain Greiner (2016,2017)
5 *
6 * Copyright (c) UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#ifndef _PTHREAD_H_
25#define _PTHREAD_H_
26
27#include <shared_syscalls.h>
28
29//////////////////////////////////////////////////////////////////////////////////////////////
30//             POSIX Threads related functions
31//////////////////////////////////////////////////////////////////////////////////////////////
32
33/*********************************************************************************************
34 * This function creates a new user thread. The <user_attr> argument is a pointer
35 * on a structure containing the thread attributes, defined in thread.h file.
36 *********************************************************************************************
37 * @ trdid       : [out] buffer for created thread identifier in process.
38 * @ user_attr   : [in]  pointer on thread attributes structure.
39 * @ start_func  : [in]  pointer on start function.
40 * @ start_args  : [in]  pointer on start function arguments.
41 * @ return 0 if success / return -1 if failure.
42 ********************************************************************************************/
43int pthread_create( pthread_t            * trdid,
44                    const pthread_attr_t * attr,
45                    void                 * start_func,
46                    void                 * start_args );
47
48/*********************************************************************************************
49 * This blocking function causes the calling thread to wait for the termination of a target
50 * thread identified by the <trdid> argument. The <exit_value> defines the buffer to store
51 * the pointer returned by the terminating thread.
52 *********************************************************************************************
53 * @ trdid       : target thread identifier in process.
54 * @ start_args  : [in]  pointer on start function arguments.
55 * @ return 0 if success / return -1 if failure.
56 ********************************************************************************************/
57int pthread_join( pthread_t    trdid,
58                  void      ** exit_value );
59
60/*********************************************************************************************
61 * This function is used to indicate that storage for the target thread, identified by the
62 * <trdid> argument can be reclaimed when the thread terminates.
63 * If target thread has not terminated, pthread_detach() will not cause it to terminate.
64 *********************************************************************************************
65 * @ trdid       : target thread identifier in process.
66 * @ return 0 if success / return -1 if failure.
67 ********************************************************************************************/
68int pthread_detach( pthread_t   trdid );
69
70/*********************************************************************************************
71 * This function terminates the execution of the calling thread, and makes the exit_value
72 * pointer available to any successful pthread_join() with the terminating thread.
73 *********************************************************************************************
74 * @ exit_vallue  : [in] pointer to be returned to parent thread if thead is attached.
75 * @ return 0 if success / return -1 if failure.
76 ********************************************************************************************/
77int pthread_exit( void * exit_value );
78
79/*********************************************************************************************
80 * This function calls the scheduler for the core running the calling thread.
81 *********************************************************************************************
82 * @ return always 0.
83 ********************************************************************************************/
84int pthread_yield();
85
86//////////////////////////////////////////////////////////////////////////////////////////////
87//                 POSIX Barriers related functions
88//
89// These functions are implemented in user space. Only the pthread_barrier_init() function
90// uses syscalls to build the distributed quad-tree infrastructure.
91//////////////////////////////////////////////////////////////////////////////////////////////
92
93/*********************************************************************************************
94 * These structures defines a hierarchical, POSIX compliant, barrier.
95 * - If the barrier attribute in the pthread_barrier_init() is NULL, it is implemented
96 *   as a simple, sense reversing barrier, localised in the calling thread cluster.
97 * - If the barrier attribute is defined, it is implemented as a hierarchical, physically
98 *   distributed quad-tree, covering all clusters specified, with the following constraints:
99 *   . The involved clusters form a mesh [x_size * y_size]
100 *   . The lower left involved cluster is cluster(0,0) 
101 *   . The number of threads in a cluster is the same in all clusters.
102 *
103 * Implementation note:
104 * - The quad three is implemented as a three dimensions array of node[x][y][l]
105 *   . [x][y] are the cluster coordinates / max values are (QDT_XMAX-1), (QDT_YMAX-1)
106 *   . [l] is the node level / 0 for terminal nodes / (QDT_LMAX-1) for the root node
107 ********************************************************************************************/
108
109#define  QDT_XMAX    16                /*! max number of clusters in a row                  */
110#define  QDT_YMAX    16                /*! max number of clusters in a column               */
111#define  QDT_LMAX    5                 /*! max depth of the quad tree                       */
112#define  QDT_YWIDTH  4                 /*! Y field in cxy, for cxy <=> (x,y) translation    */
113#define  QDT_YMASK   0xF               /*! Y field in cxy, for cxy <=> (x,y) translation    */
114
115typedef struct sqt_node_s
116{
117    volatile unsigned int sense;       /*! barrier state (toggle)                           */
118    volatile unsigned int count;       /*! number of not arrived tasks                      */
119    unsigned int          arity;       /*! number of locally expected tasks                 */
120    unsigned int          level;       /*! hierarchical level (0 is bottom)                 */
121    struct sqt_node_s   * parent;      /*! pointer on parent node (NULL for root)           */
122    struct sqt_node_s   * child[4];    /*! pointer on children node (NULL for bottom)       */
123}
124sqt_node_t;
125
126typedef struct pthread_barrier_s
127{
128    sqt_node_t          * node[QDT_XMAX][QDT_YMAX][QDT_LMAX];
129}
130pthread_barrier_t;
131
132typedef struct pthread_barrierattr_s
133{
134    unsigned int          x_size;      /*! number of clusters in a row (0 to x_size-1)      */
135    unsigned int          y_size;      /*! number of clusters in a column (0 to y_size-1)   */
136    unsigned int          nthreads;    /*! number of expected threads in a cluster          */
137}
138pthread_barrierattr_t;
139
140/*********************************************************************************************
141 * This function allocates resources required to use the barrier referenced by the <barrier>
142 * argument, and initializes the barrier from attributes referenced by the <attr> argument.
143 * If <attr> is NULL, the default barrier attributes shall be used.
144 * The results are undefined if pthread_barrier_init() is called when any thread is blocked
145 * on the barrier, or is used without first being initialized, or if pthread_barrier_init()
146 * is called specifying an already initialized barrier.
147 *********************************************************************************************
148 * @ barrier     : [in]  pointer on barrier in user space.
149 * @ attr        : [in]  pointer on attributes structure.
150 * @ count       : [in]  number of expected threads.
151 * @ return 0 if success / return EINVAL if illegal attributes.
152 ********************************************************************************************/
153int pthread_barrier_init( pthread_barrier_t           * barrier,
154                          const pthread_barrierattr_t * attr,
155                          unsigned int                  count ); 
156
157/*********************************************************************************************
158 * This function synchronizes participating threads at the barrier referenced by <barrier>.
159 * The calling is blocked until the required number of threads have called the function
160 * pthread_barrier_wait() specifying the barrier.
161 * When the required number of threads have called pthread_barrier_wait(), the constant
162 * PTHREAD_BARRIER_SERIAL_THREAD is returned to one unspecified thread and zero is returned
163 * to each of the remaining threads.
164 *********************************************************************************************
165 * @ barrier     : [in]  pointer on barrier in user space.
166 * @ return 0 if success / return EINVAL if the barrier was not properly initialized.
167 ********************************************************************************************/
168int pthread_barrier_wait( pthread_barrier_t * barrier );
169
170/*********************************************************************************************
171 * This function destroy the barrier referenced by <barrier> and release all resources used
172 * by the barrier. The effect of subsequent use of the barrier is undefined until the barrier
173 * is reinitialized by another call to pthread_barrier_init().
174 * An implementation may use this function to set barrier to an invalid value.
175 * The results are undefined if pthread_barrier_destroy() is called when a thread is blocked
176 * on the barrier, or if this function is called with an uninitialized barrier.
177 *********************************************************************************************
178 * @ barrier     : [in]  pointer on barrier in user space.
179 ********************************************************************************************/
180int pthread_barrier_destroy( pthread_barrier_t * barrier );
181   
182
183//////////////////////////////////////////////////////////////////////////////////////////////
184//                      POSIX Mutexes
185//
186// These functions are implemented in user space, and do not use syscalls.
187// This implementation uses a ticket based policy to enforce fairness.
188//////////////////////////////////////////////////////////////////////////////////////////////
189
190typedef struct pthread_mutex_s
191{
192    volatile unsigned int current;   /*! current index                                      */
193    volatile unsigned int free;      /*! next free ticket index                             */
194}
195pthread_mutex_t;
196
197typedef struct pthread_mutexattr_s
198{
199    int          bloup;              /*! unused                                             */
200}
201pthread_mutexattr_t;
202
203/*********************************************************************************************
204 * This function initialise the mutex identified by the <mutex> argument.
205 * The <attr> argument is not supported yet, and must be NULL.
206 *********************************************************************************************
207 * @ mutex     : pointer on mutex in user space.
208 * @ attr      : pointer on attributes structure / must be NULL.
209 * @ return 0 if success / return -1 if failure.
210 ********************************************************************************************/
211int pthread_mutex_init( pthread_mutex_t           * mutex,
212                        const pthread_mutexattr_t * attr );
213
214/*********************************************************************************************
215 * This function destroy the mutex identified by the <mutex> argument.
216 *********************************************************************************************
217 * @ mutex     : pointer on mutex in user space.
218 * @ return 0 if success / return -1 if failure.
219 ********************************************************************************************/
220int pthread_mutex_destroy( pthread_mutex_t * mutex );
221
222/*********************************************************************************************
223 * This bloking function locks the mutex identified by the <mutex> argument,
224 * and blocks until it becomes available.
225 *********************************************************************************************
226 * @ mutex     : pointer on mutex in user space.
227 * @ return 0 if success / return -1 if failure.
228 ********************************************************************************************/
229int pthread_mutex_lock( pthread_mutex_t * mutex );
230
231/*********************************************************************************************
232 * This function tries to lock the mutex identified by the <mutex> argument,
233 * but don't block if the mutex is locked by another thread, including the current thread.
234 *********************************************************************************************
235 * @ mutex     : pointer on mutex in user space.
236 * @ return 0 if success / return -1 if mutex already taken.
237 ********************************************************************************************/
238int pthread_mutex_trylock( pthread_mutex_t * mutex );
239
240/*********************************************************************************************
241 * This function unlocks the mutex identified by the <mutex> argument.
242 *********************************************************************************************
243 * @ mutex     : pointer on mutex in user space.
244 * @ return 0 if success / return -1 if failure.
245 ********************************************************************************************/
246int pthread_mutex_unlock( pthread_mutex_t * mutex );
247
248
249#endif  // _STDIO_H_
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