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1 /*
2  * Copyright © 2016 Advanced Micro Devices, Inc.
3  * All Rights Reserved.
4  *
5  * Permission is hereby granted, free of charge, to any person obtaining
6  * a copy of this software and associated documentation files (the
7  * "Software"), to deal in the Software without restriction, including
8  * without limitation the rights to use, copy, modify, merge, publish,
9  * distribute, sub license, and/or sell copies of the Software, and to
10  * permit persons to whom the Software is furnished to do so, subject to
11  * the following conditions:
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
14  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
15  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
16  * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS, AUTHORS
17  * AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
20  * USE OR OTHER DEALINGS IN THE SOFTWARE.
21  *
22  * The above copyright notice and this permission notice (including the
23  * next paragraph) shall be included in all copies or substantial portions
24  * of the Software.
25  */
26 
27 /* Job queue with execution in a separate thread.
28  *
29  * Jobs can be added from any thread. After that, the wait call can be used
30  * to wait for completion of the job.
31  */
32 
33 #ifndef U_QUEUE_H
34 #define U_QUEUE_H
35 
36 #include <string.h>
37 
38 #include "util/futex.h"
39 #include "util/list.h"
40 #include "util/macros.h"
41 #include "util/os_time.h"
42 #include "util/u_atomic.h"
43 #include "util/u_thread.h"
44 
45 #ifdef __cplusplus
46 extern "C" {
47 #endif
48 
49 #define UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY      (1 << 0)
50 #define UTIL_QUEUE_INIT_RESIZE_IF_FULL            (1 << 1)
51 
52 #if defined(__GNUC__) && defined(HAVE_LINUX_FUTEX_H)
53 #define UTIL_QUEUE_FENCE_FUTEX
54 #else
55 #define UTIL_QUEUE_FENCE_STANDARD
56 #endif
57 
58 #ifdef UTIL_QUEUE_FENCE_FUTEX
59 /* Job completion fence.
60  * Put this into your job structure.
61  */
62 struct util_queue_fence {
63    /* The fence can be in one of three states:
64     *  0 - signaled
65     *  1 - unsignaled
66     *  2 - unsignaled, may have waiters
67     */
68    uint32_t val;
69 };
70 
71 static inline void
util_queue_fence_init(struct util_queue_fence * fence)72 util_queue_fence_init(struct util_queue_fence *fence)
73 {
74    fence->val = 0;
75 }
76 
77 static inline void
util_queue_fence_destroy(struct util_queue_fence * fence)78 util_queue_fence_destroy(struct util_queue_fence *fence)
79 {
80    assert(fence->val == 0);
81    /* no-op */
82 }
83 
84 static inline void
util_queue_fence_signal(struct util_queue_fence * fence)85 util_queue_fence_signal(struct util_queue_fence *fence)
86 {
87    uint32_t val = p_atomic_xchg(&fence->val, 0);
88 
89    assert(val != 0);
90 
91    if (val == 2)
92       futex_wake(&fence->val, INT_MAX);
93 }
94 
95 /**
96  * Move \p fence back into unsignalled state.
97  *
98  * \warning The caller must ensure that no other thread may currently be
99  *          waiting (or about to wait) on the fence.
100  */
101 static inline void
util_queue_fence_reset(struct util_queue_fence * fence)102 util_queue_fence_reset(struct util_queue_fence *fence)
103 {
104 #ifdef NDEBUG
105    fence->val = 1;
106 #else
107    uint32_t v = p_atomic_xchg(&fence->val, 1);
108    assert(v == 0);
109 #endif
110 }
111 
112 static inline bool
util_queue_fence_is_signalled(struct util_queue_fence * fence)113 util_queue_fence_is_signalled(struct util_queue_fence *fence)
114 {
115    return fence->val == 0;
116 }
117 #endif
118 
119 #ifdef UTIL_QUEUE_FENCE_STANDARD
120 /* Job completion fence.
121  * Put this into your job structure.
122  */
123 struct util_queue_fence {
124    mtx_t mutex;
125    cnd_t cond;
126    int signalled;
127 };
128 
129 void util_queue_fence_init(struct util_queue_fence *fence);
130 void util_queue_fence_destroy(struct util_queue_fence *fence);
131 void util_queue_fence_signal(struct util_queue_fence *fence);
132 
133 /**
134  * Move \p fence back into unsignalled state.
135  *
136  * \warning The caller must ensure that no other thread may currently be
137  *          waiting (or about to wait) on the fence.
138  */
139 static inline void
util_queue_fence_reset(struct util_queue_fence * fence)140 util_queue_fence_reset(struct util_queue_fence *fence)
141 {
142    assert(fence->signalled);
143    fence->signalled = 0;
144 }
145 
146 static inline bool
util_queue_fence_is_signalled(struct util_queue_fence * fence)147 util_queue_fence_is_signalled(struct util_queue_fence *fence)
148 {
149    return fence->signalled != 0;
150 }
151 #endif
152 
153 void
154 _util_queue_fence_wait(struct util_queue_fence *fence);
155 
156 static inline void
util_queue_fence_wait(struct util_queue_fence * fence)157 util_queue_fence_wait(struct util_queue_fence *fence)
158 {
159    if (unlikely(!util_queue_fence_is_signalled(fence)))
160       _util_queue_fence_wait(fence);
161 }
162 
163 bool
164 _util_queue_fence_wait_timeout(struct util_queue_fence *fence,
165                                int64_t abs_timeout);
166 
167 /**
168  * Wait for the fence to be signaled with a timeout.
169  *
170  * \param fence the fence
171  * \param abs_timeout the absolute timeout in nanoseconds, relative to the
172  *                    clock provided by os_time_get_nano.
173  *
174  * \return true if the fence was signaled, false if the timeout occurred.
175  */
176 static inline bool
util_queue_fence_wait_timeout(struct util_queue_fence * fence,int64_t abs_timeout)177 util_queue_fence_wait_timeout(struct util_queue_fence *fence,
178                               int64_t abs_timeout)
179 {
180    if (util_queue_fence_is_signalled(fence))
181       return true;
182 
183    if (abs_timeout == (int64_t)OS_TIMEOUT_INFINITE) {
184       _util_queue_fence_wait(fence);
185       return true;
186    }
187 
188    return _util_queue_fence_wait_timeout(fence, abs_timeout);
189 }
190 
191 typedef void (*util_queue_execute_func)(void *job, int thread_index);
192 
193 struct util_queue_job {
194    void *job;
195    struct util_queue_fence *fence;
196    util_queue_execute_func execute;
197    util_queue_execute_func cleanup;
198 };
199 
200 /* Put this into your context. */
201 struct util_queue {
202    const char *name;
203    mtx_t finish_lock; /* only for util_queue_finish */
204    mtx_t lock;
205    cnd_t has_queued_cond;
206    cnd_t has_space_cond;
207    thrd_t *threads;
208    unsigned flags;
209    int num_queued;
210    unsigned num_threads;
211    int kill_threads;
212    int max_jobs;
213    int write_idx, read_idx; /* ring buffer pointers */
214    struct util_queue_job *jobs;
215 
216    /* for cleanup at exit(), protected by exit_mutex */
217    struct list_head head;
218 };
219 
220 bool util_queue_init(struct util_queue *queue,
221                      const char *name,
222                      unsigned max_jobs,
223                      unsigned num_threads,
224                      unsigned flags);
225 void util_queue_destroy(struct util_queue *queue);
226 
227 /* optional cleanup callback is called after fence is signaled: */
228 void util_queue_add_job(struct util_queue *queue,
229                         void *job,
230                         struct util_queue_fence *fence,
231                         util_queue_execute_func execute,
232                         util_queue_execute_func cleanup);
233 void util_queue_drop_job(struct util_queue *queue,
234                          struct util_queue_fence *fence);
235 
236 void util_queue_finish(struct util_queue *queue);
237 
238 int64_t util_queue_get_thread_time_nano(struct util_queue *queue,
239                                         unsigned thread_index);
240 
241 /* util_queue needs to be cleared to zeroes for this to work */
242 static inline bool
util_queue_is_initialized(struct util_queue * queue)243 util_queue_is_initialized(struct util_queue *queue)
244 {
245    return queue->threads != NULL;
246 }
247 
248 /* Convenient structure for monitoring the queue externally and passing
249  * the structure between Mesa components. The queue doesn't use it directly.
250  */
251 struct util_queue_monitoring
252 {
253    /* For querying the thread busyness. */
254    struct util_queue *queue;
255 
256    /* Counters updated by the user of the queue. */
257    unsigned num_offloaded_items;
258    unsigned num_direct_items;
259    unsigned num_syncs;
260 };
261 
262 #ifdef __cplusplus
263 }
264 #endif
265 
266 #endif
267