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2  *
3  * Copyright 2019 Red Hat.
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11  * Software is furnished to do so, subject to the following conditions:
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13  * The above copyright notice and this permission notice shall be included
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22  * SOFTWARE.
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25 
26 /**
27  * compute shader thread pool.
28  * based on threadpool.c but modified heavily to be compute shader tuned.
29  */
30 
31 #include "util/u_thread.h"
32 #include "util/u_memory.h"
33 #include "lp_cs_tpool.h"
34 
35 static int
lp_cs_tpool_worker(void * data)36 lp_cs_tpool_worker(void *data)
37 {
38    struct lp_cs_tpool *pool = data;
39    struct lp_cs_local_mem lmem;
40 
41    memset(&lmem, 0, sizeof(lmem));
42    mtx_lock(&pool->m);
43 
44    while (!pool->shutdown) {
45       struct lp_cs_tpool_task *task;
46       unsigned iter_per_thread;
47 
48       while (list_is_empty(&pool->workqueue) && !pool->shutdown)
49          cnd_wait(&pool->new_work, &pool->m);
50 
51       if (pool->shutdown)
52          break;
53 
54       task = list_first_entry(&pool->workqueue, struct lp_cs_tpool_task,
55                               list);
56 
57       unsigned this_iter = task->iter_start;
58 
59       iter_per_thread = task->iter_per_thread;
60 
61       if (task->iter_remainder &&
62           task->iter_start + task->iter_remainder == task->iter_total) {
63          task->iter_remainder--;
64          iter_per_thread = 1;
65       }
66 
67       task->iter_start += iter_per_thread;
68 
69       if (task->iter_start == task->iter_total)
70          list_del(&task->list);
71 
72       mtx_unlock(&pool->m);
73       for (unsigned i = 0; i < iter_per_thread; i++)
74          task->work(task->data, this_iter + i, &lmem);
75 
76       mtx_lock(&pool->m);
77       task->iter_finished += iter_per_thread;
78       if (task->iter_finished == task->iter_total)
79          cnd_broadcast(&task->finish);
80    }
81    mtx_unlock(&pool->m);
82    FREE(lmem.local_mem_ptr);
83    return 0;
84 }
85 
86 struct lp_cs_tpool *
lp_cs_tpool_create(unsigned num_threads)87 lp_cs_tpool_create(unsigned num_threads)
88 {
89    struct lp_cs_tpool *pool = CALLOC_STRUCT(lp_cs_tpool);
90 
91    if (!pool)
92       return NULL;
93 
94    (void) mtx_init(&pool->m, mtx_plain);
95    cnd_init(&pool->new_work);
96 
97    list_inithead(&pool->workqueue);
98    assert (num_threads <= LP_MAX_THREADS);
99    pool->num_threads = num_threads;
100    for (unsigned i = 0; i < num_threads; i++)
101       pool->threads[i] = u_thread_create(lp_cs_tpool_worker, pool);
102    return pool;
103 }
104 
105 void
lp_cs_tpool_destroy(struct lp_cs_tpool * pool)106 lp_cs_tpool_destroy(struct lp_cs_tpool *pool)
107 {
108    if (!pool)
109       return;
110 
111    mtx_lock(&pool->m);
112    pool->shutdown = true;
113    cnd_broadcast(&pool->new_work);
114    mtx_unlock(&pool->m);
115 
116    for (unsigned i = 0; i < pool->num_threads; i++) {
117       thrd_join(pool->threads[i], NULL);
118    }
119 
120    cnd_destroy(&pool->new_work);
121    mtx_destroy(&pool->m);
122    FREE(pool);
123 }
124 
125 struct lp_cs_tpool_task *
lp_cs_tpool_queue_task(struct lp_cs_tpool * pool,lp_cs_tpool_task_func work,void * data,int num_iters)126 lp_cs_tpool_queue_task(struct lp_cs_tpool *pool,
127                        lp_cs_tpool_task_func work, void *data, int num_iters)
128 {
129    struct lp_cs_tpool_task *task;
130 
131    if (pool->num_threads == 0) {
132       struct lp_cs_local_mem lmem;
133 
134       memset(&lmem, 0, sizeof(lmem));
135       for (unsigned t = 0; t < num_iters; t++) {
136          work(data, t, &lmem);
137       }
138       FREE(lmem.local_mem_ptr);
139       return NULL;
140    }
141    task = CALLOC_STRUCT(lp_cs_tpool_task);
142    if (!task) {
143       return NULL;
144    }
145 
146    task->work = work;
147    task->data = data;
148    task->iter_total = num_iters;
149 
150    task->iter_per_thread = num_iters / pool->num_threads;
151    task->iter_remainder = num_iters % pool->num_threads;
152 
153    cnd_init(&task->finish);
154 
155    mtx_lock(&pool->m);
156 
157    list_addtail(&task->list, &pool->workqueue);
158 
159    cnd_broadcast(&pool->new_work);
160    mtx_unlock(&pool->m);
161    return task;
162 }
163 
164 void
lp_cs_tpool_wait_for_task(struct lp_cs_tpool * pool,struct lp_cs_tpool_task ** task_handle)165 lp_cs_tpool_wait_for_task(struct lp_cs_tpool *pool,
166                           struct lp_cs_tpool_task **task_handle)
167 {
168    struct lp_cs_tpool_task *task = *task_handle;
169 
170    if (!pool || !task)
171       return;
172 
173    mtx_lock(&pool->m);
174    while (task->iter_finished < task->iter_total)
175       cnd_wait(&task->finish, &pool->m);
176    mtx_unlock(&pool->m);
177 
178    cnd_destroy(&task->finish);
179    FREE(task);
180    *task_handle = NULL;
181 }
182