Amend and improve VP8 multithreading implementation

[libvpx] / vp8 / encoder / encodeframe.c

diff --git a/vp8/encoder/encodeframe.c b/vp8/encoder/encodeframe.c
index b0aaa2f0bf0cf7ff8c339353692c0a9055306909..9b05cd1fcd0371489ff4e4195cd3602e546bec19 100644 (file)
--- a/vp8/encoder/encodeframe.c
+++ b/vp8/encoder/encodeframe.c
@@ -386,8 +386,8 @@ void encode_mb_row(VP8_COMP *cpi,
 #if CONFIG_MULTITHREAD
     const int nsync = cpi->mt_sync_range;
     const int rightmost_col = cm->mb_cols + nsync;
-    volatile const int *last_row_current_mb_col;
-    volatile int *current_mb_col = &cpi->mt_current_mb_col[mb_row];
+    const int *last_row_current_mb_col;
+    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];
@@ -461,17 +461,15 @@ void encode_mb_row(VP8_COMP *cpi,
         vp8_copy_mem16x16(x->src.y_buffer, x->src.y_stride, x->thismb, 16);
 
 #if CONFIG_MULTITHREAD
-        if (cpi->b_multi_threaded != 0)
-        {
-            *current_mb_col = mb_col - 1; /* set previous MB done */
+        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);
+            }
 
-            if ((mb_col & (nsync - 1)) == 0)
-            {
-                while (mb_col > (*last_row_current_mb_col - nsync))
-                {
-                    x86_pause_hint();
-                    thread_sleep(0);
-                }
+            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);
             }
         }
 #endif
@@ -616,7 +614,7 @@ void encode_mb_row(VP8_COMP *cpi,
 
 #if CONFIG_MULTITHREAD
     if (cpi->b_multi_threaded != 0)
-        *current_mb_col = rightmost_col;
+        protected_write(&cpi->pmutex[mb_row], current_mb_col, rightmost_col);
 #endif
 
     /* this is to account for the border */