third_party/aom/aom_util/aom_thread.c

   1 /*
   2  * Copyright (c) 2016, Alliance for Open Media. All rights reserved
   3  *
   4  * This source code is subject to the terms of the BSD 2 Clause License and
   5  * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
   6  * was not distributed with this source code in the LICENSE file, you can
   7  * obtain it at www.aomedia.org/license/software. If the Alliance for Open
   8  * Media Patent License 1.0 was not distributed with this source code in the
   9  * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
  10  */
  11 //
  12 // Multi-threaded worker
  13 //
  14 // Original source:
  15 //  https://chromium.googlesource.com/webm/libwebp
  16
  17 // Enable GNU extensions in glibc so that we can call pthread_setname_np().
  18 // This must be before any #include statements.
  19 #ifndef _GNU_SOURCE
  20 #define _GNU_SOURCE
  21 #endif
  22
  23 #include <assert.h>
  24 #include <string.h>  // for memset()
  25
  26 #include "config/aom_config.h"
  27
  28 #include "aom_mem/aom_mem.h"
  29 #include "aom_ports/sanitizer.h"
  30 #include "aom_util/aom_pthread.h"
  31 #include "aom_util/aom_thread.h"
  32
  33 #if CONFIG_MULTITHREAD
  34
  35 struct AVxWorkerImpl {
  36   pthread_mutex_t mutex_;
  37   pthread_cond_t condition_;
  38   pthread_t thread_;
  39 };
  40
  41 //------------------------------------------------------------------------------
  42
  43 static void execute(AVxWorker *const worker);  // Forward declaration.
  44
  45 static THREADFN thread_loop(void *ptr) {
  46   AVxWorker *const worker = (AVxWorker *)ptr;
  47 #ifdef __APPLE__
  48   if (worker->thread_name != NULL) {
  49     // Apple's version of pthread_setname_np takes one argument and operates on
  50     // the current thread only. The maximum size of the thread_name buffer was
  51     // noted in the Chromium source code and was confirmed by experiments. If
  52     // thread_name is too long, pthread_setname_np returns -1 with errno
  53     // ENAMETOOLONG (63).
  54     char thread_name[64];
  55     strncpy(thread_name, worker->thread_name, sizeof(thread_name) - 1);
  56     thread_name[sizeof(thread_name) - 1] = '\0';
  57     pthread_setname_np(thread_name);
  58   }
  59 #elif (defined(__GLIBC__) && !defined(__GNU__)) || defined(__BIONIC__)
  60   if (worker->thread_name != NULL) {
  61     // Linux and Android require names (with nul) fit in 16 chars, otherwise
  62     // pthread_setname_np() returns ERANGE (34).
  63     char thread_name[16];
  64     strncpy(thread_name, worker->thread_name, sizeof(thread_name) - 1);
  65     thread_name[sizeof(thread_name) - 1] = '\0';
  66     pthread_setname_np(pthread_self(), thread_name);
  67   }
  68 #endif
  69   pthread_mutex_lock(&worker->impl_->mutex_);
  70   for (;;) {
  71     while (worker->status_ == AVX_WORKER_STATUS_OK) {  // wait in idling mode
  72       pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
  73     }
  74     if (worker->status_ == AVX_WORKER_STATUS_WORKING) {
  75       // When worker->status_ is AVX_WORKER_STATUS_WORKING, the main thread
  76       // doesn't change worker->status_ and will wait until the worker changes
  77       // worker->status_ to AVX_WORKER_STATUS_OK. See change_state(). So the
  78       // worker can safely call execute() without holding worker->impl_->mutex_.
  79       // When the worker reacquires worker->impl_->mutex_, worker->status_ must
  80       // still be AVX_WORKER_STATUS_WORKING.
  81       pthread_mutex_unlock(&worker->impl_->mutex_);
  82       execute(worker);
  83       pthread_mutex_lock(&worker->impl_->mutex_);
  84       assert(worker->status_ == AVX_WORKER_STATUS_WORKING);
  85       worker->status_ = AVX_WORKER_STATUS_OK;
  86       // signal to the main thread that we're done (for sync())
  87       pthread_cond_signal(&worker->impl_->condition_);
  88     } else {
  89       assert(worker->status_ == AVX_WORKER_STATUS_NOT_OK);  // finish the worker
  90       break;
  91     }
  92   }
  93   pthread_mutex_unlock(&worker->impl_->mutex_);
  94   return THREAD_EXIT_SUCCESS;  // Thread is finished
  95 }
  96
  97 // main thread state control
  98 static void change_state(AVxWorker *const worker, AVxWorkerStatus new_status) {
  99   // No-op when attempting to change state on a thread that didn't come up.
 100   // Checking status_ without acquiring the lock first would result in a data
 101   // race.
 102   if (worker->impl_ == NULL) return;
 103
 104   pthread_mutex_lock(&worker->impl_->mutex_);
 105   if (worker->status_ >= AVX_WORKER_STATUS_OK) {
 106     // wait for the worker to finish
 107     while (worker->status_ != AVX_WORKER_STATUS_OK) {
 108       pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
 109     }
 110     // assign new status and release the working thread if needed
 111     if (new_status != AVX_WORKER_STATUS_OK) {
 112       worker->status_ = new_status;
 113       pthread_cond_signal(&worker->impl_->condition_);
 114     }
 115   }
 116   pthread_mutex_unlock(&worker->impl_->mutex_);
 117 }
 118
 119 #endif  // CONFIG_MULTITHREAD
 120
 121 //------------------------------------------------------------------------------
 122
 123 static void init(AVxWorker *const worker) {
 124   memset(worker, 0, sizeof(*worker));
 125   worker->status_ = AVX_WORKER_STATUS_NOT_OK;
 126 }
 127
 128 static int sync(AVxWorker *const worker) {
 129 #if CONFIG_MULTITHREAD
 130   change_state(worker, AVX_WORKER_STATUS_OK);
 131 #endif
 132   assert(worker->status_ <= AVX_WORKER_STATUS_OK);
 133   return !worker->had_error;
 134 }
 135
 136 static int reset(AVxWorker *const worker) {
 137   int ok = 1;
 138   worker->had_error = 0;
 139   if (worker->status_ < AVX_WORKER_STATUS_OK) {
 140 #if CONFIG_MULTITHREAD
 141     worker->impl_ = (AVxWorkerImpl *)aom_calloc(1, sizeof(*worker->impl_));
 142     if (worker->impl_ == NULL) {
 143       return 0;
 144     }
 145     if (pthread_mutex_init(&worker->impl_->mutex_, NULL)) {
 146       goto Error;
 147     }
 148     if (pthread_cond_init(&worker->impl_->condition_, NULL)) {
 149       pthread_mutex_destroy(&worker->impl_->mutex_);
 150       goto Error;
 151     }
 152     pthread_attr_t attr;
 153     if (pthread_attr_init(&attr)) goto Error2;
 154       // Debug ASan builds require at least ~1MiB of stack; prevents
 155       // failures on macOS arm64 where the default is 512KiB.
 156       // See: https://crbug.com/aomedia/3379
 157 #if defined(AOM_ADDRESS_SANITIZER) && defined(__APPLE__) && AOM_ARCH_ARM && \
 158     !defined(NDEBUG)
 159     size_t stacksize;
 160     if (!pthread_attr_getstacksize(&attr, &stacksize)) {
 161       const size_t kMinStackSize = 1 << 20;  // 1 MiB
 162       if (stacksize < kMinStackSize &&
 163           pthread_attr_setstacksize(&attr, kMinStackSize)) {
 164         pthread_attr_destroy(&attr);
 165         goto Error2;
 166       }
 167     }
 168 #endif
 169     pthread_mutex_lock(&worker->impl_->mutex_);
 170     ok = !pthread_create(&worker->impl_->thread_, &attr, thread_loop, worker);
 171     if (ok) worker->status_ = AVX_WORKER_STATUS_OK;
 172     pthread_mutex_unlock(&worker->impl_->mutex_);
 173     pthread_attr_destroy(&attr);
 174     if (!ok) {
 175     Error2:
 176       pthread_mutex_destroy(&worker->impl_->mutex_);
 177       pthread_cond_destroy(&worker->impl_->condition_);
 178     Error:
 179       aom_free(worker->impl_);
 180       worker->impl_ = NULL;
 181       return 0;
 182     }
 183 #else
 184     worker->status_ = AVX_WORKER_STATUS_OK;
 185 #endif
 186   } else if (worker->status_ > AVX_WORKER_STATUS_OK) {
 187     ok = sync(worker);
 188   }
 189   assert(!ok || (worker->status_ == AVX_WORKER_STATUS_OK));
 190   return ok;
 191 }
 192
 193 static void execute(AVxWorker *const worker) {
 194   if (worker->hook != NULL) {
 195     worker->had_error |= !worker->hook(worker->data1, worker->data2);
 196   }
 197 }
 198
 199 static void launch(AVxWorker *const worker) {
 200 #if CONFIG_MULTITHREAD
 201   change_state(worker, AVX_WORKER_STATUS_WORKING);
 202 #else
 203   execute(worker);
 204 #endif
 205 }
 206
 207 static void end(AVxWorker *const worker) {
 208 #if CONFIG_MULTITHREAD
 209   if (worker->impl_ != NULL) {
 210     change_state(worker, AVX_WORKER_STATUS_NOT_OK);
 211     pthread_join(worker->impl_->thread_, NULL);
 212     pthread_mutex_destroy(&worker->impl_->mutex_);
 213     pthread_cond_destroy(&worker->impl_->condition_);
 214     aom_free(worker->impl_);
 215     worker->impl_ = NULL;
 216   }
 217 #else
 218   worker->status_ = AVX_WORKER_STATUS_NOT_OK;
 219   assert(worker->impl_ == NULL);
 220 #endif
 221   assert(worker->status_ == AVX_WORKER_STATUS_NOT_OK);
 222 }
 223
 224 //------------------------------------------------------------------------------
 225
 226 static AVxWorkerInterface g_worker_interface = { init,   reset,   sync,
 227                                                  launch, execute, end };
 228
 229 int aom_set_worker_interface(const AVxWorkerInterface *const winterface) {
 230   if (winterface == NULL || winterface->init == NULL ||
 231       winterface->reset == NULL || winterface->sync == NULL ||
 232       winterface->launch == NULL || winterface->execute == NULL ||
 233       winterface->end == NULL) {
 234     return 0;
 235   }
 236   g_worker_interface = *winterface;
 237   return 1;
 238 }
 239
 240 const AVxWorkerInterface *aom_get_worker_interface(void) {
 241   return &g_worker_interface;
 242 }
 243
 244 //------------------------------------------------------------------------------