Change performance schema alignment to CPU_LEVEL1_DCACHE_LINESIZE

Inspired by Alexey Kopytov's pull request mysql/mysql-server#42
the PFS_ALIGNED is set to CPU_LEVEL1_DCACHE_LINESIZE if defined.

A more complete patch in MySQL-5.7:
mysql/mysql-server@0d55a07

Inspired by the complete patch the volatile global variables of the performance
schema have been quantified by PFS_ALIGNED.

Author: grooverdan

storage/perfschema/pfs_digest.cc

@@ -47,7 +47,7 @@ bool flag_statements_digest= true;
   Current index in Stat array where new record is to be inserted.
   index 0 is reserved for "all else" case when entire array is full.
 */
-volatile uint32 digest_index;
+PFS_ALIGNED volatile uint32 digest_index;
 bool digest_full= false;
 
 LF_HASH digest_hash;

storage/perfschema/pfs_events_stages.cc

@@ -41,7 +41,7 @@ bool flag_events_stages_history_long= false;
 /** True if EVENTS_STAGES_HISTORY_LONG circular buffer is full. */
 bool events_stages_history_long_full= false;
 /** Index in EVENTS_STAGES_HISTORY_LONG circular buffer. */
-volatile uint32 events_stages_history_long_index= 0;
+PFS_ALIGNED volatile uint32 events_stages_history_long_index= 0;
 /** EVENTS_STAGES_HISTORY_LONG circular buffer. */
 PFS_events_stages *events_stages_history_long_array= NULL;
 

storage/perfschema/pfs_events_statements.cc

@@ -41,7 +41,7 @@ bool flag_events_statements_history_long= false;
 /** True if EVENTS_STATEMENTS_HISTORY_LONG circular buffer is full. */
 bool events_statements_history_long_full= false;
 /** Index in EVENTS_STATEMENTS_HISTORY_LONG circular buffer. */
-volatile uint32 events_statements_history_long_index= 0;
+PFS_ALIGNED volatile uint32 events_statements_history_long_index= 0;
 /** EVENTS_STATEMENTS_HISTORY_LONG circular buffer. */
 PFS_events_statements *events_statements_history_long_array= NULL;
 static unsigned char *h_long_stmts_digest_token_array= NULL;

storage/perfschema/pfs_events_waits.cc

@@ -45,7 +45,7 @@ bool flag_thread_instrumentation= false;
 /** True if EVENTS_WAITS_HISTORY_LONG circular buffer is full. */
 bool events_waits_history_long_full= false;
 /** Index in EVENTS_WAITS_HISTORY_LONG circular buffer. */
-volatile uint32 events_waits_history_long_index= 0;
+PFS_ALIGNED volatile uint32 events_waits_history_long_index= 0;
 /** EVENTS_WAITS_HISTORY_LONG circular buffer. */
 PFS_events_waits *events_waits_history_long_array= NULL;
 

storage/perfschema/pfs_lock.h

@@ -21,6 +21,7 @@
   Performance schema internal locks (declarations).
 */
 
+#include "pfs_global.h"
 #include "pfs_atomic.h"
 
 /**
@@ -79,7 +80,7 @@ struct pfs_lock
     The version number is stored in the high 30 bits.
     The state is stored in the low 2 bits.
   */
-  volatile uint32 m_version_state;
+  PFS_ALIGNED volatile uint32 m_version_state;
 
   /** Returns true if the record is free. */
   bool is_free(void)