Merge pull request #64 from AGSaidi/master

Update cpu relax functions

Author: rpgolshan

ext/linux/include/lk_atomics.h

@@ -251,7 +251,9 @@ static inline uint16_t xchg_release16(uint16_t *ptr, uint16_t val) {
 static inline void cpu_relax (void) {
 #if defined(__x86_64__)
 	asm volatile ("pause" : : : "memory" );
-#elif defined (__arch64__)
+#elif defined (__aarch64__) && defined(RELAX_IS_ISB)
+	asm volatile ("isb" : : : "memory" );
+#elif defined (__aarch64__)
 	asm volatile ("yield" : : : "memory" );
 #endif
 }

ext/mysql/include/ut_atomics.h

@@ -21,10 +21,10 @@ this program; if not, write to the Free Software Foundation, Inc.,
 
 #if defined(__x86_64__)
 #define UT_RELAX_CPU() asm volatile ("rep; nop")
-#elif defined(__AARCH64__)
+#elif defined(__aarch64__)
 // Theoretically we could emit a yield here but MySQL doesn't do it
 // and most ARM cores are likely to NOP it anyway
-#define UT_RELAX_CPU() asm volatile ("":::"memory")
+#define UT_RELAX_CPU() asm volatile ("isb":::"memory")
 #else
 #define UT_RELAX_CPU() asm volatile ("":::"memory")
 #endif