FFmpeg: libavcodec/pthread_slice.c Source File

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pthread_slice.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * FFmpeg is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
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8  *
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11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with FFmpeg; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18 
19 /**
20  * @file
21  * Slice multithreading support functions
22  * @see doc/multithreading.txt
23  */
24 
25 #include "config.h"
26 
27 #include "avcodec.h"
28 #include "codec_internal.h"
29 #include "internal.h"
30 #include "pthread_internal.h"
31 #include "thread.h"
32 
33 #include "libavutil/avassert.h"
34 #include "libavutil/common.h"
35 #include "libavutil/cpu.h"
36 #include "libavutil/mem.h"
37 #include "libavutil/thread.h"
38 #include "libavutil/slicethread.h"
39 
40  typedef int (action_func)(AVCodecContext *c, void *arg);
41  typedef int (action_func2)(AVCodecContext *c, void *arg, int jobnr, int threadnr);
42  typedef int (main_func)(AVCodecContext *c);
43 
44  typedef struct Progress {
45   pthread_cond_t cond;
46   pthread_mutex_t mutex;
47 } Progress;
48 
49  typedef struct SliceThreadContext {
50   AVSliceThread *thread;
51   action_func *func;
52   action_func2 *func2;
53   main_func *mainfunc;
54   void *args;
55   int *rets;
56   int job_size;
57 
58   int *entries;
59   int entries_count;
60   int thread_count;
61   Progress *progress;
62 } SliceThreadContext;
63 
64  static void main_function(void *priv) {
65  AVCodecContext *avctx = priv;
66  SliceThreadContext *c = avctx->internal->thread_ctx;
67  c->mainfunc(avctx);
68 }
69 
70  static void worker_func(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads)
71 {
72  AVCodecContext *avctx = priv;
73  SliceThreadContext *c = avctx->internal->thread_ctx;
74  int ret;
75 
76  ret = c->func ? c->func(avctx, (char *)c->args + c->job_size * jobnr)
77  : c->func2(avctx, c->args, jobnr, threadnr);
78  if (c->rets)
79  c->rets[jobnr] = ret;
80 }
81 
82  void ff_slice_thread_free(AVCodecContext *avctx)
83 {
84  SliceThreadContext *c = avctx->internal->thread_ctx;
85  int i;
86 
87  avpriv_slicethread_free(&c->thread);
88 
89  for (i = 0; i < c->thread_count; i++) {
90  Progress *const progress = &c->progress[i];
91  pthread_mutex_destroy(&progress->mutex);
92  pthread_cond_destroy(&progress->cond);
93  }
94 
95  av_freep(&c->entries);
96  av_freep(&c->progress);
97  av_freep(&avctx->internal->thread_ctx);
98 }
99 
100  static int thread_execute(AVCodecContext *avctx, action_func* func, void *arg, int *ret, int job_count, int job_size)
101 {
102  SliceThreadContext *c = avctx->internal->thread_ctx;
103 
104  if (!(avctx->active_thread_type&FF_THREAD_SLICE) || avctx->thread_count <= 1)
105  return avcodec_default_execute(avctx, func, arg, ret, job_count, job_size);
106 
107  if (job_count <= 0)
108  return 0;
109 
110  c->job_size = job_size;
111  c->args = arg;
112  c->func = func;
113  c->rets = ret;
114 
115  avpriv_slicethread_execute(c->thread, job_count, !!c->mainfunc );
116  return 0;
117 }
118 
119  static int thread_execute2(AVCodecContext *avctx, action_func2* func2, void *arg, int *ret, int job_count)
120 {
121  SliceThreadContext *c = avctx->internal->thread_ctx;
122  c->func2 = func2;
123  return thread_execute(avctx, NULL, arg, ret, job_count, 0);
124 }
125 
126  int ff_slice_thread_execute_with_mainfunc(AVCodecContext *avctx, action_func2* func2, main_func *mainfunc, void *arg, int *ret, int job_count)
127 {
128  SliceThreadContext *c = avctx->internal->thread_ctx;
129  c->func2 = func2;
130  c->mainfunc = mainfunc;
131  return thread_execute(avctx, NULL, arg, ret, job_count, 0);
132 }
133 
134  int ff_slice_thread_init(AVCodecContext *avctx)
135 {
136  SliceThreadContext *c;
137  int thread_count = avctx->thread_count;
138  void (*mainfunc)(void *);
139 
140  // We cannot do this in the encoder init as the threads are created before
141  if (av_codec_is_encoder(avctx->codec) &&
142  avctx->codec_id == AV_CODEC_ID_MPEG1VIDEO &&
143  avctx->height > 2800)
144  thread_count = avctx->thread_count = 1;
145 
146  if (!thread_count) {
147  int nb_cpus = av_cpu_count();
148  if (avctx->height)
149  nb_cpus = FFMIN(nb_cpus, (avctx->height+15)/16);
150  // use number of cores + 1 as thread count if there is more than one
151  if (nb_cpus > 1)
152  thread_count = avctx->thread_count = FFMIN(nb_cpus + 1, MAX_AUTO_THREADS);
153  else
154  thread_count = avctx->thread_count = 1;
155  }
156 
157  if (thread_count <= 1) {
158  avctx->active_thread_type = 0;
159  return 0;
160  }
161 
162  avctx->internal->thread_ctx = c = av_mallocz(sizeof(*c));
163  mainfunc = ffcodec(avctx->codec)->caps_internal & FF_CODEC_CAP_SLICE_THREAD_HAS_MF ? &main_function : NULL;
164  if (!c || (thread_count = avpriv_slicethread_create(&c->thread, avctx, worker_func, mainfunc, thread_count)) <= 1) {
165  if (c)
166  avpriv_slicethread_free(&c->thread);
167  av_freep(&avctx->internal->thread_ctx);
168  avctx->thread_count = 1;
169  avctx->active_thread_type = 0;
170  return 0;
171  }
172  avctx->thread_count = thread_count;
173 
174  avctx->execute = thread_execute;
175  avctx->execute2 = thread_execute2;
176  return 0;
177 }
178 
179  int av_cold ff_slice_thread_init_progress(AVCodecContext *avctx)
180 {
181  SliceThreadContext *const p = avctx->internal->thread_ctx;
182  int err, i = 0, thread_count = avctx->thread_count;
183 
184  p->progress = av_calloc(thread_count, sizeof(*p->progress));
185  if (!p->progress) {
186  err = AVERROR(ENOMEM);
187  goto fail;
188  }
189 
190  for (; i < thread_count; i++) {
191  Progress *const progress = &p->progress[i];
192  err = pthread_mutex_init(&progress->mutex, NULL);
193  if (err) {
194  err = AVERROR(err);
195  goto fail;
196  }
197  err = pthread_cond_init (&progress->cond, NULL);
198  if (err) {
199  err = AVERROR(err);
200  pthread_mutex_destroy(&progress->mutex);
201  goto fail;
202  }
203  }
204  err = 0;
205 fail:
206  p->thread_count = i;
207  return err;
208 }
209 
210  void ff_thread_report_progress2(AVCodecContext *avctx, int field, int thread, int n)
211 {
212  SliceThreadContext *p = avctx->internal->thread_ctx;
213  Progress *const progress = &p->progress[thread];
214  int *entries = p->entries;
215 
216  pthread_mutex_lock(&progress->mutex);
217  entries[field] +=n;
218  pthread_cond_signal(&progress->cond);
219  pthread_mutex_unlock(&progress->mutex);
220 }
221 
222  void ff_thread_await_progress2(AVCodecContext *avctx, int field, int thread, int shift)
223 {
224  SliceThreadContext *p = avctx->internal->thread_ctx;
225  Progress *progress;
226  int *entries = p->entries;
227 
228  if (!entries || !field) return;
229 
230  thread = thread ? thread - 1 : p->thread_count - 1;
231  progress = &p->progress[thread];
232 
233  pthread_mutex_lock(&progress->mutex);
234  while ((entries[field - 1] - entries[field]) < shift){
235  pthread_cond_wait(&progress->cond, &progress->mutex);
236  }
237  pthread_mutex_unlock(&progress->mutex);
238 }
239 
240  int ff_alloc_entries(AVCodecContext *avctx, int count)
241 {
242  if (avctx->active_thread_type & FF_THREAD_SLICE) {
243  SliceThreadContext *p = avctx->internal->thread_ctx;
244 
245  if (p->entries) {
246  av_freep(&p->entries);
247  }
248 
249  p->entries = av_calloc(count, sizeof(*p->entries));
250  if (!p->entries) {
251  p->entries_count = 0;
252  return AVERROR(ENOMEM);
253  }
254  p->entries_count = count;
255  }
256 
257  return 0;
258 }
259 
260  void ff_reset_entries(AVCodecContext *avctx)
261 {
262  SliceThreadContext *p = avctx->internal->thread_ctx;
263  memset(p->entries, 0, p->entries_count * sizeof(int));
264 }
func
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:68
SliceThreadContext::args
void * args
Definition: pthread_slice.c:54
pthread_mutex_t
_fmutex pthread_mutex_t
Definition: os2threads.h:53
FF_CODEC_CAP_SLICE_THREAD_HAS_MF
#define FF_CODEC_CAP_SLICE_THREAD_HAS_MF
Codec initializes slice-based threading with a main function.
Definition: codec_internal.h:61
AVERROR
Filter the word "frame" indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
thread.h
pthread_mutex_init
static av_always_inline int pthread_mutex_init(pthread_mutex_t *mutex, const pthread_mutexattr_t *attr)
Definition: os2threads.h:104
MAX_AUTO_THREADS
#define MAX_AUTO_THREADS
Definition: pthread_internal.h:26
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void avpriv_slicethread_execute(AVSliceThread *ctx, int nb_jobs, int execute_main)
Execute slice threading.
Definition: slicethread.c:247
SliceThreadContext::mainfunc
main_func * mainfunc
Definition: pthread_slice.c:53
internal.h
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void ff_slice_thread_free(AVCodecContext *avctx)
Definition: pthread_slice.c:82
SliceThreadContext::entries_count
int entries_count
Definition: pthread_slice.c:59
Progress::cond
pthread_cond_t cond
Definition: pthread_slice.c:45
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struct AVSliceThread AVSliceThread
Definition: slicethread.h:22
thread.h
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static void main_function(void *priv)
Definition: pthread_slice.c:64
SliceThreadContext::thread_count
int thread_count
Definition: pthread_slice.c:60
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const struct AVCodec * codec
Definition: avcodec.h:398
SliceThreadContext::progress
Progress * progress
Definition: pthread_slice.c:61
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int avpriv_slicethread_create(AVSliceThread **pctx, void *priv, void(*worker_func)(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads), void(*main_func)(void *priv), int nb_threads)
Create slice threading context.
Definition: slicethread.c:238
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#define fail()
Definition: checkasm.h:131
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thread count is used to decide how many independent tasks should be passed to execute()
Definition: avcodec.h:1463
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void ff_reset_entries(AVCodecContext *avctx)
Definition: pthread_slice.c:260
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Definition: pthread_slice.c:52
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void ff_thread_report_progress2(AVCodecContext *avctx, int field, int thread, int n)
Definition: pthread_slice.c:210
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static double(*const func2[])(void *, double, double)
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#define av_cold
Definition: attributes.h:90
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void ff_thread_await_progress2(AVCodecContext *avctx, int field, int thread, int shift)
Definition: pthread_slice.c:222
SliceThreadContext::job_size
int job_size
Definition: pthread_slice.c:56
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it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this field
Definition: writing_filters.txt:78
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enum AVCodecID codec_id
Definition: avcodec.h:399
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Definition: jacosubdec.c:67
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Definition: filter_design.txt:179
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Definition: coverity.c:32
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int * rets
Definition: pthread_slice.c:55
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struct AVCodecInternal * internal
Private context used for internal data.
Definition: avcodec.h:424
Progress
Definition: pthread_slice.c:44
SliceThreadContext::thread
AVSliceThread * thread
Definition: pthread_slice.c:50
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int * entries
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int av_cold ff_slice_thread_init_progress(AVCodecContext *avctx)
Definition: pthread_slice.c:179
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static void worker_func(void *priv, int jobnr, int threadnr, int nb_jobs, int nb_threads)
Definition: pthread_slice.c:70
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
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#define pthread_mutex_unlock(a)
Definition: ffprobe.c:77
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@ AV_CODEC_ID_MPEG1VIDEO
Definition: codec_id.h:51
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Definition: cpu.c:195
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Definition: pthread_slice.c:49
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static int thread_execute2(AVCodecContext *avctx, action_func2 *func2, void *arg, int *ret, int job_count)
Definition: pthread_slice.c:119
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Definition: pthread_slice.c:100
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Definition: pthread_slice.c:51
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static const av_always_inline FFCodec * ffcodec(const AVCodec *codec)
Definition: codec_internal.h:273
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#define FF_THREAD_SLICE
Decode more than one part of a single frame at once.
Definition: avcodec.h:1475
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Definition: avcodec.c:45
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Definition: pthread_slice.c:134
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Definition: os2threads.h:112
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int ff_slice_thread_execute_with_mainfunc(AVCodecContext *avctx, action_func2 *func2, main_func *mainfunc, void *arg, int *ret, int job_count)
Definition: pthread_slice.c:126
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Definition: codec_internal.h:121
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Definition: macros.h:49
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Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
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Definition: avcodec.h:562
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Definition: filter_design.txt:187
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main external API structure.
Definition: avcodec.h:389
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int active_thread_type
Which multithreading methods are in use by the codec.
Definition: avcodec.h:1482
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int(* execute)(struct AVCodecContext *c, int(*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size)
The codec may call this to execute several independent things.
Definition: avcodec.h:1514
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Definition: internal.h:63
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void avpriv_slicethread_free(AVSliceThread **pctx)
Destroy slice threading context.
Definition: slicethread.c:252
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static av_always_inline int pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *attr)
Definition: os2threads.h:133
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int
Definition: ffmpeg_filter.c:153
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int(* execute2)(struct AVCodecContext *c, int(*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count)
The codec may call this to execute several independent things.
Definition: avcodec.h:1533
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int ff_alloc_entries(AVCodecContext *avctx, int count)
Definition: pthread_slice.c:240
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#define pthread_mutex_lock(a)
Definition: ffprobe.c:73
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