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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
     72 util_queue_fence_init(struct util_queue_fence *fence)
     73 {
     74    fence->val = 0;
     75 }
     76 
     77 static inline void
     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
     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
    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
    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
    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
    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
    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
    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
    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