From d8ea2a492e83e418c7075532eda3d55202718bea Mon Sep 17 00:00:00 2001
From: Jung-uk Kim <jkim@FreeBSD.org>
Date: Tue, 15 Mar 2011 17:14:26 +0000
Subject: [PATCH] Unconditionally use binuptime(9) for get_cyclecount(9) on
 i386.  Since this function is almost exclusively used for random harvesting,
 there is no need for micro-optimization.  Adjust the manual page accordingly.

---
 share/man/man9/get_cyclecount.9 | 8 ++++----
 sys/i386/include/cpu.h          | 9 ++-------
 2 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/share/man/man9/get_cyclecount.9 b/share/man/man9/get_cyclecount.9
index e3be78e59d21..470b7be3a5a4 100644
--- a/share/man/man9/get_cyclecount.9
+++ b/share/man/man9/get_cyclecount.9
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 24, 2009
+.Dd March 15, 2011
 .Dt GET_CYCLECOUNT 9
 .Os
 .Sh NAME
@@ -65,14 +65,14 @@ do not have such a register,
 so
 .Fn get_cyclecount
 on these platforms
-returns a (non-monotonic) combination of numbers
+returns a (monotonic) combination of numbers
 represented by the
 structure returned by
 .Xr binuptime 9 .
 .Pp
 The
-.Tn Pentium
-processors all use the
+.Tn AMD64 and Intel 64
+processors use the
 .Li TSC
 register.
 .Pp
diff --git a/sys/i386/include/cpu.h b/sys/i386/include/cpu.h
index bee0b5fa31b9..7ceb1968a2d4 100644
--- a/sys/i386/include/cpu.h
+++ b/sys/i386/include/cpu.h
@@ -70,15 +70,10 @@ void	swi_vm(void *);
 static __inline uint64_t
 get_cyclecount(void)
 {
-#if defined(I486_CPU) || defined(KLD_MODULE)
 	struct bintime bt;
 
-	if (!tsc_present) {
-		binuptime(&bt);
-		return ((uint64_t)bt.sec << 56 | bt.frac >> 8);
-	}
-#endif
-	return (rdtsc());
+	binuptime(&bt);
+	return ((uint64_t)bt.sec << 56 | bt.frac >> 8);
 }
 
 #endif