svn commit: r216274 - in head/sys: amd64/amd64 i386/i386

[Jung-uk Kim]

Author: jkim
Date: Tue Dec  7 22:23:26 2010
New Revision: 216274
URL: http://svn.freebsd.org/changeset/base/216274

Log:
  Now the P-state invariant TSC is probed early enough, do not register event
  handlers for CPU freqency changes when it is found P-state invariant.
  Adjust a comment about non-existent tsc_freq_max() while I am here.

Modified:
  head/sys/amd64/amd64/tsc.c
  head/sys/i386/i386/tsc.c

Modified: head/sys/amd64/amd64/tsc.c
==============================================================================
--- head/sys/amd64/amd64/tsc.c	Tue Dec  7 22:16:37 2010	(r216273)
+++ head/sys/amd64/amd64/tsc.c	Tue Dec  7 22:23:26 2010	(r216274)
@@ -118,13 +118,15 @@ init_TSC(void)
 	}
 
 	/*
-	 * Inform CPU accounting about our boot-time clock rate.  Once the
-	 * system is finished booting, we will get the real max clock rate
-	 * via tsc_freq_max().  This also will be updated if someone loads
-	 * a cpufreq driver after boot that discovers a new max frequency.
+	 * Inform CPU accounting about our boot-time clock rate.  This 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)
+		return;
+
 	/* Register to find out about changes in CPU frequency. */
 	tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change,
 	    tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST);
@@ -169,9 +171,6 @@ tsc_levels_changed(void *arg, int unit)
 	int count, error;
 	uint64_t max_freq;
 
-	if (tsc_is_invariant)
-		return;
-
 	/* Only use values from the first CPU, assuming all are equal. */
 	if (unit != 0)
 		return;
@@ -205,8 +204,7 @@ static void
 tsc_freq_changing(void *arg, const struct cf_level *level, int *status)
 {
 
-	if (*status != 0 || timecounter != &tsc_timecounter ||
-	    tsc_is_invariant)
+	if (*status != 0 || timecounter != &tsc_timecounter)
 		return;
 
 	printf("timecounter TSC must not be in use when "
@@ -222,7 +220,7 @@ tsc_freq_changed(void *arg, const struct
 	 * If there was an error during the transition or
 	 * TSC is P-state invariant, don't do anything.
 	 */
-	if (status != 0 || tsc_is_invariant)
+	if (status != 0)
 		return;
 
 	/* Total setting for this level gives the new frequency in MHz. */

Modified: head/sys/i386/i386/tsc.c
==============================================================================
--- head/sys/i386/i386/tsc.c	Tue Dec  7 22:16:37 2010	(r216273)
+++ head/sys/i386/i386/tsc.c	Tue Dec  7 22:23:26 2010	(r216274)
@@ -127,13 +127,15 @@ init_TSC(void)
 	}
 
 	/*
-	 * Inform CPU accounting about our boot-time clock rate.  Once the
-	 * system is finished booting, we will get the real max clock rate
-	 * via tsc_freq_max().  This also will be updated if someone loads
-	 * a cpufreq driver after boot that discovers a new max frequency.
+	 * Inform CPU accounting about our boot-time clock rate.  This 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)
+		return;
+
 	/* Register to find out about changes in CPU frequency. */
 	tsc_pre_tag = EVENTHANDLER_REGISTER(cpufreq_pre_change,
 	    tsc_freq_changing, NULL, EVENTHANDLER_PRI_FIRST);
@@ -197,9 +199,6 @@ tsc_levels_changed(void *arg, int unit)
 	int count, error;
 	uint64_t max_freq;
 
-	if (tsc_is_invariant)
-		return;
-
 	/* Only use values from the first CPU, assuming all are equal. */
 	if (unit != 0)
 		return;
@@ -233,8 +232,7 @@ static void
 tsc_freq_changing(void *arg, const struct cf_level *level, int *status)
 {
 
-	if (*status != 0 || timecounter != &tsc_timecounter ||
-	    tsc_is_invariant)
+	if (*status != 0 || timecounter != &tsc_timecounter)
 		return;
 
 	printf("timecounter TSC must not be in use when "
@@ -250,7 +248,7 @@ tsc_freq_changed(void *arg, const struct
 	 * If there was an error during the transition or
 	 * TSC is P-state invariant, don't do anything.
 	 */
-	if (status != 0 || tsc_is_invariant)
+	if (status != 0)
 		return;
 
 	/* Total setting for this level gives the new frequency in MHz. */