Index: storage/innobase/buf/buf0dblwr.cc
===================================================================
--- storage/innobase/buf/buf0dblwr.cc	(版本 3920)
+++ storage/innobase/buf/buf0dblwr.cc	(工作副本)
@@ -46,6 +46,8 @@
 #ifdef UNIV_PFS_MUTEX
 /* Key to register the mutex with performance schema */
 UNIV_INTERN mysql_pfs_key_t	buf_dblwr_mutex_key;
+
+UNIV_INTERN mysql_pfs_key_t     buf_dblwr_s_mutex_key;
 #endif /* UNIV_PFS_RWLOCK */
 
 /** The doublewrite buffer */
@@ -54,6 +56,8 @@
 /** Set to TRUE when the doublewrite buffer is being created */
 UNIV_INTERN ibool	buf_dblwr_being_created = FALSE;
 
+#define DBLWR_MUTEX_EXTEND
+
 /****************************************************************//**
 Determines if a page number is located inside the doublewrite buffer.
 @return TRUE if the location is inside the two blocks of the
@@ -130,6 +134,9 @@
 
 	mutex_create(buf_dblwr_mutex_key,
 		     &buf_dblwr->mutex, SYNC_DOUBLEWRITE);
+        
+        mutex_create(buf_dblwr_s_mutex_key,
+                     &buf_dblwr->s_mutex, SYNC_DOUBLEWRITE);
 
 	buf_dblwr->first_free = 0;
 	buf_dblwr->s_reserved = 0;
@@ -567,7 +574,8 @@
 	buf_dblwr->in_use = NULL;
 
 	mutex_free(&buf_dblwr->mutex);
-	mem_free(buf_dblwr);
+	mutex_free(&buf_dblwr->s_mutex);
+       mem_free(buf_dblwr);
 	buf_dblwr = NULL;
 }
 
@@ -914,6 +922,8 @@
 		goto try_again;
 	}
 
+        export_vars.innodb_dblwr_batch_flush++;
+
 	zip_size = buf_page_get_zip_size(bpage);
 
 	if (zip_size) {
@@ -1001,10 +1011,17 @@
 	}
 
 retry:
-	mutex_enter(&buf_dblwr->mutex);
+#ifdef DBLWR_MUTEX_EXTEND        
+        mutex_enter(&buf_dblwr->s_mutex);
+#else        
+        mutex_enter(&buf_dblwr->mutex);
+#endif        
 	if (buf_dblwr->s_reserved == n_slots) {
-
+#ifdef DBLWR_MUTEX_EXTEND
+                mutex_exit(&buf_dblwr->s_mutex);
+#else                
 		mutex_exit(&buf_dblwr->mutex);
+#endif                
 		/* All slots are reserved. Since it involves two IOs
 		during the processing a sleep of 10ms should be
 		enough. */
@@ -1018,13 +1035,20 @@
 			break;
 		}
 	}
+        
+        export_vars.innodb_dblwr_single_flush++;
 
+
 	/* We are guaranteed to find a slot. */
 	ut_a(i < size);
 	buf_dblwr->in_use[i] = TRUE;
 	buf_dblwr->s_reserved++;
 	buf_dblwr->buf_block_arr[i] = bpage;
+#ifdef DBLWR_MUTEX_EXTEND
+        mutex_exit(&buf_dblwr->s_mutex);
+#else                
 	mutex_exit(&buf_dblwr->mutex);
+#endif  
 
 	/* Lets see if we are going to write in the first or second
 	block of the doublewrite buffer. */
@@ -1077,9 +1101,13 @@
 	/* Sync the writes to the disk. */
 	buf_flush_sync_datafiles();
 
-	mutex_enter(&buf_dblwr->mutex);
-
-	buf_dblwr->s_reserved--;
+#ifdef DBLWR_MUTEX_EXTEND        
+        mutex_enter(&buf_dblwr->s_mutex);
+#else        
+        mutex_enter(&buf_dblwr->mutex);
+#endif   
+	
+        buf_dblwr->s_reserved--;
 	buf_dblwr->buf_block_arr[i] = NULL;
 	buf_dblwr->in_use[i] = FALSE;
 
@@ -1087,7 +1115,10 @@
 	srv_stats.dblwr_pages_written.inc();
 	srv_stats.dblwr_writes.inc();
 
-	mutex_exit(&(buf_dblwr->mutex));
-
+#ifdef DBLWR_MUTEX_EXTEND
+        mutex_exit(&buf_dblwr->s_mutex);
+#else                
+	mutex_exit(&buf_dblwr->mutex);
+#endif  
 }
 #endif /* !UNIV_HOTBACKUP */
Index: storage/innobase/handler/ha_innodb.cc
===================================================================
--- storage/innobase/handler/ha_innodb.cc	(版本 3920)
+++ storage/innobase/handler/ha_innodb.cc	(工作副本)
@@ -639,6 +639,10 @@
   {"purge_view_trx_id_age",
   (char*) &export_vars.innodb_purge_view_trx_id_age,      SHOW_LONG},
 #endif /* UNIV_DEBUG */
+  {"dblwr_single_flush",
+  (char*) &export_vars.innodb_dblwr_single_flush, SHOW_LONGLONG},
+  {"dblwr_batch_flush",
+  (char*) &export_vars.innodb_dblwr_batch_flush, SHOW_LONGLONG},
   {NullS, NullS, SHOW_LONG}
 };
 
Index: storage/innobase/include/srv0srv.h
===================================================================
--- storage/innobase/include/srv0srv.h	(版本 3920)
+++ storage/innobase/include/srv0srv.h	(工作副本)
@@ -848,6 +848,8 @@
 	ulint innodb_purge_view_trx_id_age;	/*!< rw_max_trx_id
 						- purged view's min trx_id */
 #endif /* UNIV_DEBUG */
+        long long innodb_dblwr_batch_flush;
+        long long innodb_dblwr_single_flush;
 };
 
 /** Thread slot in the thread table.  */
Index: storage/innobase/include/buf0dblwr.h
===================================================================
--- storage/innobase/include/buf0dblwr.h	(版本 3920)
+++ storage/innobase/include/buf0dblwr.h	(工作副本)
@@ -115,7 +115,8 @@
 struct buf_dblwr_t{
 	ib_mutex_t	mutex;	/*!< mutex protecting the first_free field and
 				write_buf */
-	ulint	block1;		/*!< the page number of the first
+	ib_mutex_t      s_mutex;
+        ulint	block1;		/*!< the page number of the first
 				doublewrite block (64 pages) */
 	ulint	block2;		/*!< page number of the second block */
 	ulint	first_free;	/*!< first free position in write_buf measured