Use the isb instruction instead of yield for spin locks on arm
isb introduces a small delay which is closer to the x86 pause instruction.
diff --git a/configure.ac b/configure.ac
index 49a12ac..3303bad 100644
--- a/configure.ac
+++ b/configure.ac
@@ -425,14 +425,15 @@
;;
aarch64|arm*)
HAVE_CPU_SPINWAIT=1
- AC_CACHE_VAL([je_cv_yield],
- [JE_COMPILABLE([yield instruction], [],
- [[__asm__ volatile("yield"); return 0;]],
- [je_cv_yield])])
- if test "x${je_cv_yield}" = "xyes" ; then
- CPU_SPINWAIT='__asm__ volatile("yield")'
+ dnl isb is a better equivalent to the pause instruction on x86.
+ AC_CACHE_VAL([je_cv_isb],
+ [JE_COMPILABLE([isb instruction], [],
+ [[__asm__ volatile("isb"); return 0;]],
+ [je_cv_isb])])
+ if test "x${je_cv_isb}" = "xyes" ; then
+ CPU_SPINWAIT='__asm__ volatile("isb")'
fi
- ;;
+ ;;
*)
HAVE_CPU_SPINWAIT=0
;;
