svn commit: r219672 - in head: share/man/man9 sys/i386/include

Jung-uk Kim jkim at FreeBSD.org
Tue Mar 15 17:14:27 UTC 2011


Author: jkim
Date: Tue Mar 15 17:14:26 2011
New Revision: 219672
URL: http://svn.freebsd.org/changeset/base/219672

Log:
  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.

Modified:
  head/share/man/man9/get_cyclecount.9
  head/sys/i386/include/cpu.h

Modified: head/share/man/man9/get_cyclecount.9
==============================================================================
--- head/share/man/man9/get_cyclecount.9	Tue Mar 15 16:50:17 2011	(r219671)
+++ head/share/man/man9/get_cyclecount.9	Tue Mar 15 17:14:26 2011	(r219672)
@@ -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

Modified: head/sys/i386/include/cpu.h
==============================================================================
--- head/sys/i386/include/cpu.h	Tue Mar 15 16:50:17 2011	(r219671)
+++ head/sys/i386/include/cpu.h	Tue Mar 15 17:14:26 2011	(r219672)
@@ -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


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