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>

1 files changed, 7 insertions, 6 deletions

diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index f37930954d15..eed156851f5d 100644
--- a/arch/x86/kernel/tsc_sync.c
+++ b/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);
         }
 
         /*