diff --git a/sys/amd64/amd64/tsc.c b/sys/amd64/amd64/tsc.c
index 847c1eb..44cc7dc 100644
--- a/sys/amd64/amd64/tsc.c
+++ b/sys/amd64/amd64/tsc.c
@@ -49,7 +49,7 @@ __FBSDID("$FreeBSD$");
 uint64_t	tsc_freq;
 int		tsc_is_broken;
 int		tsc_is_invariant;
-static eventhandler_tag tsc_levels_tag, tsc_pre_tag, tsc_post_tag;
+static eventhandler_tag /*tsc_levels_tag,*/ tsc_pre_tag, tsc_post_tag;
 
 SYSCTL_INT(_kern_timecounter, OID_AUTO, invariant_tsc, CTLFLAG_RDTUN,
     &tsc_is_invariant, 0, "Indicates whether the TSC is P-state invariant");
@@ -67,7 +67,9 @@ static void tsc_freq_changed(void *arg, const struct cf_level *level,
 static void tsc_freq_changing(void *arg, const struct cf_level *level,
     int *status);
 static	unsigned tsc_get_timecount(struct timecounter *tc);
+#if 0
 static void tsc_levels_changed(void *arg, int unit);
+#endif
 
 static struct timecounter tsc_timecounter = {
 	tsc_get_timecount,	/* get_timecount */
@@ -100,15 +102,20 @@ init_TSC(void)
 	 * via tsc_freq_max().  This also will be updated if someone loads
 	 * a cpufreq driver after boot that discovers a new max frequency.
 	 */
-	set_cputicker(rdtsc, tsc_freq, 1);
+	if (tsc_is_invariant)
+		set_cputicker(rdtsc, tsc_freq, 1);
+	else
+		set_cputicker(NULL, 0, 0);
 
 	/* Register to find out about changes in CPU frequency. */
 	tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change,
 	    tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST);
 	tsc_post_tag = EVENTHANDLER_REGISTER(cpufreq_post_change,
 	    tsc_freq_changed, NULL, EVENTHANDLER_PRI_FIRST);
+#if 0
 	tsc_levels_tag = EVENTHANDLER_REGISTER(cpufreq_levels_changed,
 	    tsc_levels_changed, NULL, EVENTHANDLER_PRI_ANY);
+#endif
 }
 
 void
@@ -134,6 +141,7 @@ init_TSC_tc(void)
 	}
 }
 
+#if 0
 /*
  * When cpufreq levels change, find out about the (new) max frequency.  We
  * use this to update CPU accounting in case it got a lower estimate at boot.
@@ -170,6 +178,7 @@ tsc_levels_changed(void *arg, int unit)
 		printf("tsc_levels_changed: no max freq found\n");
 	free(levels, M_TEMP);
 }
+#endif
 
 /*
  * If the TSC timecounter is in use, veto the pending change.  It may be