libitm: Put gl_wt global lock on separate cache line.

	libitm/
	* method-gl.cc (gl_wt_dispatch::orec): Put on separate cacheline.

From-SVN: r184403

libitm/ChangeLog

 2012-02-20  Torvald Riegel  <triegel@redhat.com>
 
+	* method-gl.cc (gl_wt_dispatch::orec): Put on separate cacheline.
+
+2012-02-20  Torvald Riegel  <triegel@redhat.com>
+
 	* method-gl.cc (gl_wt_dispatch::rollback): Optimize memory orders.
 
 2012-02-20  Torvald Riegel  <triegel@redhat.com>

libitm/method-gl.cc

@@ -41,7 +41,8 @@ struct gl_mg : public method_group
   static gtm_word clear_locked(gtm_word l) { return l & ~LOCK_BIT; }
 
   // The global ownership record.
-  atomic<gtm_word> orec;
+  // No tail-padding necessary (the virtual functions aren't used frequently).
+  atomic<gtm_word> orec __attribute__((aligned(HW_CACHELINE_SIZE)));
 
   virtual void init()
   {
@@ -52,7 +53,6 @@ struct gl_mg : public method_group
   virtual void fini() { }
 };
 
-// TODO cacheline padding
 static gl_mg o_gl_mg;