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>
diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index f379309..eed1568 100644
--- a/arch/x86/kernel/tsc_sync.c
+++ b/arch/x86/kernel/tsc_sync.c
@@ -114,13 +114,12 @@
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 @@
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);
}
/*
