[PATCH 6/6] x86: Limit number of per cpu TSC sync messages

Mike Travis
2009-11-16T21:08:03Z

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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>
---
arch/x86/kernel/tsc_sync.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

--- linux.orig/arch/x86/kernel/tsc_sync.c
+++ linux/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);
}

/*

--