x86: Limit number of per cpu TSC sync messages

Limit the number of per cpu TSC sync messages by only printing
to the console if an error occurs, otherwise print as a DEBUG
message.

The info message "Skipping synchronization ..." is only printed
after the last cpu has booted.

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091118002222.181053000@alcatraz.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/tsc_sync.c

@@ -114,13 +114,12 @@ void __cpuinit check_tsc_sync_source(int cpu)
 		return;
 
 	if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) {
-		printk_once(KERN_INFO "Skipping synchronization checks as TSC is reliable.\n");
+		if (cpu == (nr_cpu_ids-1) || system_state != SYSTEM_BOOTING)
+			pr_info(
+			"Skipped synchronization checks as TSC is reliable.\n");
 		return;
 	}
 
-	pr_info("checking TSC synchronization [CPU#%d -> CPU#%d]:",
-		smp_processor_id(), cpu);
-
 	/*
 	 * Reset it - in case this is a second bootup:
 	 */
@@ -142,12 +141,14 @@ void __cpuinit check_tsc_sync_source(int cpu)
 		cpu_relax();
 
 	if (nr_warps) {
-		printk("\n");
+		pr_warning("TSC synchronization [CPU#%d -> CPU#%d]:\n",
+			smp_processor_id(), cpu);
 		pr_warning("Measured %Ld cycles TSC warp between CPUs, "
 			   "turning off TSC clock.\n", max_warp);
 		mark_tsc_unstable("check_tsc_sync_source failed");
 	} else {
-		printk(" passed.\n");
+		pr_debug("TSC synchronization [CPU#%d -> CPU#%d]: passed\n",
+			smp_processor_id(), cpu);
 	}
 
 	/*