From 4cd1de2f48e8c825073be4f658de7827d8c3cb26 Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@suse.de>
Date: Wed, 2 May 2007 19:27:21 +0200
Subject: [PATCH] --- yaml --- r: 53935 b: refs/heads/master c:
 c5bcb5635a03da3158f121ae20ccbbf72b4fc62a h: refs/heads/master i:   53933:
 032357b6b4f4f7b853c4661512803e1808c56647   53931:
 0fd0401fb0df4e05db2451870592eef2b147fb6d   53927:
 8c9a1e0d951d40c9fa510f708bfbda5555dca207   53919:
 b6b981bccb5f944e93a5c11a04f6dcf210cb74fc v: v3

---
 [refs]                       | 2 +-
 trunk/include/asm-i386/tsc.h | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index ddb15f6a0d78..13c98a418be9 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 9bccb23dc5fc2d268ab676e2d4212d29e230fd86
+refs/heads/master: c5bcb5635a03da3158f121ae20ccbbf72b4fc62a
diff --git a/trunk/include/asm-i386/tsc.h b/trunk/include/asm-i386/tsc.h
index 0181f9df7539..3f3c1fa000b4 100644
--- a/trunk/include/asm-i386/tsc.h
+++ b/trunk/include/asm-i386/tsc.h
@@ -37,6 +37,15 @@ static __always_inline cycles_t get_cycles_sync(void)
 	unsigned long long ret;
 	unsigned eax;
 
+	/*
+  	 * Use RDTSCP if possible; it is guaranteed to be synchronous
+ 	 * and doesn't cause a VMEXIT on Hypervisors
+	 */
+	alternative_io(ASM_NOP3, ".byte 0x0f,0x01,0xf9", X86_FEATURE_RDTSCP,
+			 	 "=A" (ret), "0" (0ULL) : "ecx", "memory");
+	if (ret)
+		return ret;
+
 	/*
 	 * Don't do an additional sync on CPUs where we know
 	 * RDTSC is already synchronous: