From 8e2b83e73332e6d28af06a51a457e2d6b323620b Mon Sep 17 00:00:00 2001
From: Mikael Ronstrom <mikael@mysql.com>
Date: Wed, 10 Dec 2008 14:02:52 +0100
Subject: Added a PAUSE instruction to the SPIN loop according to
 recommendation from Intel.

---
 configure.in | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'configure.in')

diff --git a/configure.in b/configure.in
index d7f250959d1..be6a4a33c65 100644
--- a/configure.in
+++ b/configure.in
@@ -2342,6 +2342,17 @@ fi
 fi
 #---END:
 
+#Check for x86 PAUSE instruction
+AC_MSG_CHECKING("for x86 PAUSE instruction")
+AC_TRY_COMPILE(
+[],
+[{__asm__ __volatile__ ("pause");}],
+x86_pause_exists=yes, x86_pause_exists=no)
+if test "$x86_pause_exists" = "yes"
+then
+  AC_DEFINE([HAVE_PAUSE_INSTRUCTION], [1], [Does x86 PAUSE instruction exist])
+fi
+
 # Check if pthread_attr_setscope() exists
 AC_CACHE_CHECK("for pthread_attr_setscope", mysql_cv_pthread_attr_setscope,
 AC_TRY_LINK(
-- 
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