[tip:x86/urgent] x86: Reduce verbosity of "TSC is reliable" message

From: tip-bot for Roland Dreier
Date: Thu Sep 24 2009 - 05:38:38 EST


Commit-ID: ea01c0d7315d6e3218fd22a6947c5b09305fcf65
Gitweb: http://git.kernel.org/tip/ea01c0d7315d6e3218fd22a6947c5b09305fcf65
Author: Roland Dreier <rdreier@xxxxxxxxx>
AuthorDate: Wed, 23 Sep 2009 15:33:23 -0700
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 24 Sep 2009 11:35:19 +0200

x86: Reduce verbosity of "TSC is reliable" message

On modern systems, the kernel prints the message

Skipping synchronization checks as TSC is reliable.

once for every non-boot CPU.

This gets kind of ridiculous on huge systems; for example, on a
64-thread system I was lucky enough to get:

$ dmesg | grep 'TSC is reliable' | wc
63 567 4221

There's no point to doing this for every CPU, since the code is
just checking the boot CPU anyway, so change this to a
printk_once() to make the message appears only once.

Signed-off-by: Roland Dreier <rolandd@xxxxxxxxx>
LKML-Reference: <adazl8l2swc.fsf@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
arch/x86/kernel/tsc_sync.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/tsc_sync.c b/arch/x86/kernel/tsc_sync.c
index 027b5b4..f379309 100644
--- a/arch/x86/kernel/tsc_sync.c
+++ b/arch/x86/kernel/tsc_sync.c
@@ -114,7 +114,7 @@ void __cpuinit check_tsc_sync_source(int cpu)
return;

if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE)) {
- pr_info("Skipping synchronization checks as TSC is reliable.\n");
+ printk_once(KERN_INFO "Skipping synchronization checks as TSC is reliable.\n");
return;
}

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