linux-kernel - [tip:x86/urgent] x86/tsc: Print tsc_khz, when it differs from cpu

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Date:   Sun, 14 Jan 2018 03:44:19 -0800
From:   tip-bot for Len Brown <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, linux-kernel@...r.kernel.org,
        len.brown@...el.com, hpa@...or.com, mingo@...nel.org
Subject: [tip:x86/urgent] x86/tsc: Print tsc_khz, when it differs from
 cpu_khz

Commit-ID:  4b5b2127238e689ee18aa6752959751dd61c4c73
Gitweb:     https://git.kernel.org/tip/4b5b2127238e689ee18aa6752959751dd61c4c73
Author:     Len Brown <len.brown@...el.com>
AuthorDate: Fri, 22 Dec 2017 00:27:56 -0500
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Sun, 14 Jan 2018 12:14:50 +0100

x86/tsc: Print tsc_khz, when it differs from cpu_khz

If CPU and TSC frequency are the same the printout of the CPU frequency is
valid for the TSC as well:

      tsc: Detected 2900.000 MHz processor

If the TSC frequency is different there is no information in dmesg. Add a
conditional printout:

  tsc: Detected 2904.000 MHz TSC

Signed-off-by: Len Brown <len.brown@...el.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: peterz@...radead.org
Link: https://lkml.kernel.org/r/537b342debcd8e8aebc8d631015dcdf9f9ba8a26.1513920414.git.len.brown@intel.com

---
 arch/x86/kernel/tsc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 3bf4df7..e169e85 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1316,6 +1316,12 @@ void __init tsc_init(void)
 		(unsigned long)cpu_khz / 1000,
 		(unsigned long)cpu_khz % 1000);
 
+	if (cpu_khz != tsc_khz) {
+		pr_info("Detected %lu.%03lu MHz TSC",
+			(unsigned long)tsc_khz / 1000,
+			(unsigned long)tsc_khz % 1000);
+	}
+
 	/* Sanitize TSC ADJUST before cyc2ns gets initialized */
 	tsc_store_and_check_tsc_adjust(true);