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Revert "Amend and improve VP8 multithreading implementation"

Reverted the patch because of possible performance issue.

Change-Id: I49944f827ccd38ed194c9f8d9cb9036fa9bf79e1

--- a/vp8/common/threading.h

+++ b/vp8/common/threading.h

@@ -185,46 +185,6 @@

 #define x86_pause_hint()

 #endif

-#include "vpx_util/vpx_thread.h"

-

-static INLINE void mutex_lock(pthread_mutex_t *const mutex) {

-  const int kMaxTryLocks = 4000;

-  int locked = 0;

-  int i;

-

-  for (i = 0; i < kMaxTryLocks; ++i) {

-    if (!pthread_mutex_trylock(mutex)) {

-      locked = 1;

-      break;

-    }

-  }

-

-  if (!locked) pthread_mutex_lock(mutex);

-}

-

-static INLINE int protected_read(pthread_mutex_t *const mutex, const int *p) {

-  int ret;

-  mutex_lock(mutex);

-  ret = *p;

-  pthread_mutex_unlock(mutex);

-  return ret;

-}

-

-static INLINE void sync_read(pthread_mutex_t *const mutex, int mb_col,

-                             const int *last_row_current_mb_col,

-                             const int nsync) {

-  while (mb_col > (protected_read(mutex, last_row_current_mb_col) - nsync)) {

-    x86_pause_hint();

-    thread_sleep(0);

-  }

-}

-

-static INLINE void protected_write(pthread_mutex_t *mutex, int *p, int v) {

-  mutex_lock(mutex);

-  *p = v;

-  pthread_mutex_unlock(mutex);

-}

-

 #endif /* CONFIG_OS_SUPPORT && CONFIG_MULTITHREAD */

 #ifdef __cplusplus

--- a/vp8/decoder/onyxd_int.h

+++ b/vp8/decoder/onyxd_int.h

@@ -70,8 +70,7 @@

 #if CONFIG_MULTITHREAD

   /* variable for threading */

-

-  int b_multithreaded_rd;

+  volatile int b_multithreaded_rd;

   int max_threads;

   int current_mb_col_main;

   unsigned int decoding_thread_count;

@@ -80,8 +79,6 @@

   int mt_baseline_filter_level[MAX_MB_SEGMENTS];

   int sync_range;

   int *mt_current_mb_col; /* Each row remembers its already decoded column. */

-  pthread_mutex_t *pmutex;

-  pthread_mutex_t mt_mutex; /* mutex for b_multithreaded_rd */

   unsigned char **mt_yabove_row; /* mb_rows x width */

   unsigned char **mt_uabove_row;

--- a/vp8/decoder/threading.c

+++ b/vp8/decoder/threading.c

@@ -50,6 +50,9 @@

     mbd->subpixel_predict8x8 = xd->subpixel_predict8x8;

     mbd->subpixel_predict16x16 = xd->subpixel_predict16x16;

+    mbd->mode_info_context = pc->mi + pc->mode_info_stride * (i + 1);

+    mbd->mode_info_stride = pc->mode_info_stride;

+

     mbd->frame_type = pc->frame_type;

     mbd->pre = xd->pre;

     mbd->dst = xd->dst;

@@ -248,8 +251,8 @@

 static void mt_decode_mb_rows(VP8D_COMP *pbi, MACROBLOCKD *xd,

                               int start_mb_row) {

-  const int *last_row_current_mb_col;

-  int *current_mb_col;

+  volatile const int *last_row_current_mb_col;

+  volatile int *current_mb_col;

   int mb_row;

   VP8_COMMON *pc = &pbi->common;

   const int nsync = pbi->sync_range;

@@ -286,9 +289,6 @@

   xd->up_available = (start_mb_row != 0);

-  xd->mode_info_context = pc->mi + pc->mode_info_stride * start_mb_row;

-  xd->mode_info_stride = pc->mode_info_stride;

-

   for (mb_row = start_mb_row; mb_row < pc->mb_rows;

        mb_row += (pbi->decoding_thread_count + 1)) {

     int recon_yoffset, recon_uvoffset;

@@ -355,15 +355,14 @@

                              xd->dst.uv_stride);

     }

-    for (mb_col = 0; mb_col < pc->mb_cols; ++mb_col) {

-      if (((mb_col - 1) % nsync) == 0) {

-        pthread_mutex_t *mutex = &pbi->pmutex[mb_row];

-        protected_write(mutex, current_mb_col, mb_col - 1);

-      }

+    for (mb_col = 0; mb_col < pc->mb_cols; mb_col++) {

+      *current_mb_col = mb_col - 1;

-      if (mb_row && !(mb_col & (nsync - 1))) {

-        pthread_mutex_t *mutex = &pbi->pmutex[mb_row - 1];

-        sync_read(mutex, mb_col, last_row_current_mb_col, nsync);

+      if ((mb_col & (nsync - 1)) == 0) {

+        while (mb_col > (*last_row_current_mb_col - nsync)) {

+          x86_pause_hint();

+          thread_sleep(0);

+        }

       }

       /* Distance of MB to the various image edges.

@@ -549,7 +548,7 @@

     }

     /* last MB of row is ready just after extension is done */

-    protected_write(&pbi->pmutex[mb_row], current_mb_col, mb_col + nsync);

+    *current_mb_col = mb_col + nsync;

     ++xd->mode_info_context; /* skip prediction column */

     xd->up_available = 1;

@@ -569,10 +568,10 @@

   ENTROPY_CONTEXT_PLANES mb_row_left_context;

   while (1) {

-    if (protected_read(&pbi->mt_mutex, &pbi->b_multithreaded_rd) == 0) break;

+    if (pbi->b_multithreaded_rd == 0) break;

     if (sem_wait(&pbi->h_event_start_decoding[ithread]) == 0) {

-      if (protected_read(&pbi->mt_mutex, &pbi->b_multithreaded_rd) == 0) {

+      if (pbi->b_multithreaded_rd == 0) {

         break;

       } else {

         MACROBLOCKD *xd = &mbrd->mbd;

@@ -592,7 +591,6 @@

   pbi->b_multithreaded_rd = 0;

   pbi->allocated_decoding_thread_count = 0;

-  pthread_mutex_init(&pbi->mt_mutex, NULL);

   /* limit decoding threads to the max number of token partitions */

   core_count = (pbi->max_threads > 8) ? 8 : pbi->max_threads;

@@ -633,16 +631,7 @@

 void vp8mt_de_alloc_temp_buffers(VP8D_COMP *pbi, int mb_rows) {

   int i;

-  if (protected_read(&pbi->mt_mutex, &pbi->b_multithreaded_rd)) {

-    /* De-allocate mutex */

-    if (pbi->pmutex != NULL) {

-      for (i = 0; i < mb_rows; ++i) {

-        pthread_mutex_destroy(&pbi->pmutex[i]);

-      }

-      vpx_free(pbi->pmutex);

-      pbi->pmutex = NULL;

-    }

-

+  if (pbi->b_multithreaded_rd) {

     vpx_free(pbi->mt_current_mb_col);

     pbi->mt_current_mb_col = NULL;

@@ -709,7 +698,7 @@

   int i;

   int uv_width;

-  if (protected_read(&pbi->mt_mutex, &pbi->b_multithreaded_rd)) {

+  if (pbi->b_multithreaded_rd) {

     vp8mt_de_alloc_temp_buffers(pbi, prev_mb_rows);

     /* our internal buffers are always multiples of 16 */

@@ -727,15 +716,6 @@

     uv_width = width >> 1;

-    /* Allocate mutex */

-    CHECK_MEM_ERROR(pbi->pmutex,

-                    vpx_malloc(sizeof(*pbi->pmutex) * pc->mb_rows));

-    if (pbi->pmutex) {

-      for (i = 0; i < pc->mb_rows; ++i) {

-        pthread_mutex_init(&pbi->pmutex[i], NULL);

-      }

-    }

-

     /* Allocate an int for each mb row. */

     CALLOC_ARRAY(pbi->mt_current_mb_col, pc->mb_rows);

@@ -778,10 +758,10 @@

 void vp8_decoder_remove_threads(VP8D_COMP *pbi) {

   /* shutdown MB Decoding thread; */

-  if (protected_read(&pbi->mt_mutex, &pbi->b_multithreaded_rd)) {

+  if (pbi->b_multithreaded_rd) {

     int i;

-    protected_write(&pbi->mt_mutex, &pbi->b_multithreaded_rd, 0);

+    pbi->b_multithreaded_rd = 0;

     /* allow all threads to exit */

     for (i = 0; i < pbi->allocated_decoding_thread_count; ++i) {

@@ -807,7 +787,6 @@

     vpx_free(pbi->de_thread_data);

     pbi->de_thread_data = NULL;

   }

-  pthread_mutex_destroy(&pbi->mt_mutex);

 }

 void vp8mt_decode_mb_rows(VP8D_COMP *pbi, MACROBLOCKD *xd) {

--- a/vp8/encoder/encodeframe.c

+++ b/vp8/encoder/encodeframe.c

@@ -345,8 +345,8 @@

 #if CONFIG_MULTITHREAD

   const int nsync = cpi->mt_sync_range;

   const int rightmost_col = cm->mb_cols + nsync;

-  const int *last_row_current_mb_col;

-  int *current_mb_col = &cpi->mt_current_mb_col[mb_row];

+  volatile const int *last_row_current_mb_col;

+  volatile int *current_mb_col = &cpi->mt_current_mb_col[mb_row];

   if ((cpi->b_multi_threaded != 0) && (mb_row != 0)) {

     last_row_current_mb_col = &cpi->mt_current_mb_col[mb_row - 1];

@@ -419,14 +419,13 @@

 #if CONFIG_MULTITHREAD

     if (cpi->b_multi_threaded != 0) {

-      if (((mb_col - 1) % nsync) == 0) {

-        pthread_mutex_t *mutex = &cpi->pmutex[mb_row];

-        protected_write(mutex, current_mb_col, mb_col - 1);

-      }

+      *current_mb_col = mb_col - 1; /* set previous MB done */

-      if (mb_row && !(mb_col & (nsync - 1))) {

-        pthread_mutex_t *mutex = &cpi->pmutex[mb_row - 1];

-        sync_read(mutex, mb_col, last_row_current_mb_col, nsync);

+      if ((mb_col & (nsync - 1)) == 0) {

+        while (mb_col > (*last_row_current_mb_col - nsync)) {

+          x86_pause_hint();

+          thread_sleep(0);

+        }

       }

     }

 #endif

@@ -566,9 +565,7 @@

                     xd->dst.u_buffer + 8, xd->dst.v_buffer + 8);

 #if CONFIG_MULTITHREAD

-  if (cpi->b_multi_threaded != 0) {

-    protected_write(&cpi->pmutex[mb_row], current_mb_col, rightmost_col);

-  }

+  if (cpi->b_multi_threaded != 0) *current_mb_col = rightmost_col;

 #endif

   /* this is to account for the border */

--- a/vp8/encoder/ethreading.c

+++ b/vp8/encoder/ethreading.c

@@ -25,11 +25,11 @@

   VP8_COMMON *cm = &cpi->common;

   while (1) {

-    if (protected_read(&cpi->mt_mutex, &cpi->b_multi_threaded) == 0) break;

+    if (cpi->b_multi_threaded == 0) break;

     if (sem_wait(&cpi->h_event_start_lpf) == 0) {

       /* we're shutting down */

-      if (protected_read(&cpi->mt_mutex, &cpi->b_multi_threaded) == 0) break;

+      if (cpi->b_multi_threaded == 0) break;

       vp8_loopfilter_frame(cpi, cm);

@@ -47,7 +47,7 @@

   ENTROPY_CONTEXT_PLANES mb_row_left_context;

   while (1) {

-    if (protected_read(&cpi->mt_mutex, &cpi->b_multi_threaded) == 0) break;

+    if (cpi->b_multi_threaded == 0) break;

     if (sem_wait(&cpi->h_event_start_encoding[ithread]) == 0) {

       const int nsync = cpi->mt_sync_range;

@@ -65,11 +65,8 @@

       int *totalrate = &mbri->totalrate;

       /* we're shutting down */

-      if (protected_read(&cpi->mt_mutex, &cpi->b_multi_threaded) == 0) break;

+      if (cpi->b_multi_threaded == 0) break;

-      xd->mode_info_context = cm->mi + cm->mode_info_stride * (ithread + 1);

-      xd->mode_info_stride = cm->mode_info_stride;

-

       for (mb_row = ithread + 1; mb_row < cm->mb_rows;

            mb_row += (cpi->encoding_thread_count + 1)) {

         int recon_yoffset, recon_uvoffset;

@@ -79,8 +76,8 @@

         int recon_y_stride = cm->yv12_fb[ref_fb_idx].y_stride;

         int recon_uv_stride = cm->yv12_fb[ref_fb_idx].uv_stride;

         int map_index = (mb_row * cm->mb_cols);

-        const int *last_row_current_mb_col;

-        int *current_mb_col = &cpi->mt_current_mb_col[mb_row];

+        volatile const int *last_row_current_mb_col;

+        volatile int *current_mb_col = &cpi->mt_current_mb_col[mb_row];

 #if (CONFIG_REALTIME_ONLY & CONFIG_ONTHEFLY_BITPACKING)

         vp8_writer *w = &cpi->bc[1 + (mb_row % num_part)];

@@ -106,14 +103,13 @@

         /* for each macroblock col in image */

         for (mb_col = 0; mb_col < cm->mb_cols; ++mb_col) {

-          if (((mb_col - 1) % nsync) == 0) {

-            pthread_mutex_t *mutex = &cpi->pmutex[mb_row];

-            protected_write(mutex, current_mb_col, mb_col - 1);

-          }

+          *current_mb_col = mb_col - 1;

-          if (mb_row && !(mb_col & (nsync - 1))) {

-            pthread_mutex_t *mutex = &cpi->pmutex[mb_row - 1];

-            sync_read(mutex, mb_col, last_row_current_mb_col, nsync);

+          if ((mb_col & (nsync - 1)) == 0) {

+            while (mb_col > (*last_row_current_mb_col - nsync)) {

+              x86_pause_hint();

+              thread_sleep(0);

+            }

           }

 #if CONFIG_REALTIME_ONLY & CONFIG_ONTHEFLY_BITPACKING

@@ -285,7 +281,7 @@

         vp8_extend_mb_row(&cm->yv12_fb[dst_fb_idx], xd->dst.y_buffer + 16,

                           xd->dst.u_buffer + 8, xd->dst.v_buffer + 8);

-        protected_write(&cpi->pmutex[mb_row], current_mb_col, mb_col + nsync);

+        *current_mb_col = mb_col + nsync;

         /* this is to account for the border */

         xd->mode_info_context++;

@@ -456,6 +452,9 @@

     mb->partition_info = x->pi + x->e_mbd.mode_info_stride * (i + 1);

+    mbd->mode_info_context = cm->mi + x->e_mbd.mode_info_stride * (i + 1);

+    mbd->mode_info_stride = cm->mode_info_stride;

+

     mbd->frame_type = cm->frame_type;

     mb->src = *cpi->Source;

@@ -494,8 +493,6 @@

   cpi->b_multi_threaded = 0;

   cpi->encoding_thread_count = 0;

-  pthread_mutex_init(&cpi->mt_mutex, NULL);

-

   if (cm->processor_core_count > 1 && cpi->oxcf.multi_threaded > 1) {

     int ithread;

     int th_count = cpi->oxcf.multi_threaded - 1;

@@ -554,7 +551,7 @@

     if (rc) {

       /* shutdown other threads */

-      protected_write(&cpi->mt_mutex, &cpi->b_multi_threaded, 0);

+      cpi->b_multi_threaded = 0;

       for (--ithread; ithread >= 0; ithread--) {

         pthread_join(cpi->h_encoding_thread[ithread], 0);

         sem_destroy(&cpi->h_event_start_encoding[ithread]);

@@ -567,8 +564,6 @@

       vpx_free(cpi->mb_row_ei);

       vpx_free(cpi->en_thread_data);

-      pthread_mutex_destroy(&cpi->mt_mutex);

-

       return -1;

     }

@@ -583,7 +578,7 @@

       if (rc) {

         /* shutdown other threads */

-        protected_write(&cpi->mt_mutex, &cpi->b_multi_threaded, 0);

+        cpi->b_multi_threaded = 0;

         for (--ithread; ithread >= 0; ithread--) {

           sem_post(&cpi->h_event_start_encoding[ithread]);

           pthread_join(cpi->h_encoding_thread[ithread], 0);

@@ -599,8 +594,6 @@

         vpx_free(cpi->mb_row_ei);

         vpx_free(cpi->en_thread_data);

-        pthread_mutex_destroy(&cpi->mt_mutex);

-

         return -2;

       }

     }

@@ -609,9 +602,9 @@

 }

 void vp8cx_remove_encoder_threads(VP8_COMP *cpi) {

-  if (protected_read(&cpi->mt_mutex, &cpi->b_multi_threaded)) {

+  if (cpi->b_multi_threaded) {

     /* shutdown other threads */

-    protected_write(&cpi->mt_mutex, &cpi->b_multi_threaded, 0);

+    cpi->b_multi_threaded = 0;

     {

       int i;

@@ -636,6 +629,5 @@

     vpx_free(cpi->mb_row_ei);

     vpx_free(cpi->en_thread_data);

   }

-  pthread_mutex_destroy(&cpi->mt_mutex);

 }

 #endif

--- a/vp8/encoder/onyx_if.c

+++ b/vp8/encoder/onyx_if.c

@@ -445,18 +445,6 @@

   cpi->mb.pip = 0;

 #if CONFIG_MULTITHREAD

-  /* De-allocate mutex */

-  if (cpi->pmutex != NULL) {

-    VP8_COMMON *const pc = &cpi->common;

-    int i;

-

-    for (i = 0; i < pc->mb_rows; ++i) {

-      pthread_mutex_destroy(&cpi->pmutex[i]);

-    }

-    vpx_free(cpi->pmutex);

-    cpi->pmutex = NULL;

-  }

-

   vpx_free(cpi->mt_current_mb_col);

   cpi->mt_current_mb_col = NULL;

 #endif

@@ -1086,9 +1074,6 @@

   int width = cm->Width;

   int height = cm->Height;

-#if CONFIG_MULTITHREAD

-  int prev_mb_rows = cm->mb_rows;

-#endif

   if (vp8_alloc_frame_buffers(cm, width, height)) {

     vpx_internal_error(&cpi->common.error, VPX_CODEC_MEM_ERROR,

@@ -1178,25 +1163,6 @@

   }

   if (cpi->oxcf.multi_threaded > 1) {

-    int i;

-

-    /* De-allocate and re-allocate mutex */

-    if (cpi->pmutex != NULL) {

-      for (i = 0; i < prev_mb_rows; ++i) {

-        pthread_mutex_destroy(&cpi->pmutex[i]);

-      }

-      vpx_free(cpi->pmutex);

-      cpi->pmutex = NULL;

-    }

-

-    CHECK_MEM_ERROR(cpi->pmutex,

-                    vpx_malloc(sizeof(*cpi->pmutex) * cm->mb_rows));

-    if (cpi->pmutex) {

-      for (i = 0; i < cm->mb_rows; ++i) {

-        pthread_mutex_init(&cpi->pmutex[i], NULL);

-      }

-    }

-

     vpx_free(cpi->mt_current_mb_col);

     CHECK_MEM_ERROR(cpi->mt_current_mb_col,

                     vpx_malloc(sizeof(*cpi->mt_current_mb_col) * cm->mb_rows));

--- a/vp8/encoder/onyx_int.h

+++ b/vp8/encoder/onyx_int.h

@@ -505,8 +505,6 @@

 #if CONFIG_MULTITHREAD

   /* multithread data */

-  pthread_mutex_t *pmutex;

-  pthread_mutex_t mt_mutex; /* mutex for b_multi_threaded */

   int *mt_current_mb_col;

   int mt_sync_range;

   int b_multi_threaded;