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Message-Id: <1219822736-18628-2-git-send-email-yhlu.kernel@gmail.com>
Date: Wed, 27 Aug 2008 00:38:56 -0700
From: Yinghai Lu <yhlu.kernel@...il.com>
To: Ingo Molnar <mingo@...e.hu>, Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Yinghai Lu <yhlu.kernel@...il.com>
Subject: [PATCH] x86: printk_time to use tsc before cpu_clock is ready
so can get tsc value on printk at first.
for debug delay with big system with a lot of memory.
need to apply after
[PATCH] printk_time: prepare stub for using other than cpu_clock
Signed-off-by: Yinghai Lu <yhlu.kernel@...il.com>
---
arch/x86/kernel/cpu/common.c | 11 +++++++++++
arch/x86/kernel/cpu/common_64.c | 12 ++++++++++++
2 files changed, 23 insertions(+)
Index: linux-2.6/arch/x86/kernel/cpu/common.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/common.c
+++ linux-2.6/arch/x86/kernel/cpu/common.c
@@ -647,6 +647,15 @@ __setup("clearcpuid=", setup_disablecpui
cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;
+static unsigned long long tsc_clock(int cpu)
+{
+ unsigned long long t;
+
+ rdtscll(t);
+
+ return t;
+}
+
void __init early_cpu_init(void)
{
struct cpu_vendor_dev *cvdev;
@@ -657,6 +666,8 @@ void __init early_cpu_init(void)
cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
early_cpu_detect();
+ if (cpu_has_tsc)
+ set_printk_time_clock(tsc_clock);
validate_pat_support(&boot_cpu_data);
}
Index: linux-2.6/arch/x86/kernel/cpu/common_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/common_64.c
+++ linux-2.6/arch/x86/kernel/cpu/common_64.c
@@ -249,6 +249,15 @@ static void __cpuinit detect_nopl(struct
}
}
+static unsigned long long tsc_clock(int cpu)
+{
+ unsigned long long t;
+
+ rdtscll(t);
+
+ return t;
+}
+
static void __cpuinit early_identify_cpu(struct cpuinfo_x86 *c);
void __init early_cpu_init(void)
@@ -261,6 +270,9 @@ void __init early_cpu_init(void)
cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
early_cpu_support_print();
early_identify_cpu(&boot_cpu_data);
+
+ if (cpu_has_tsc)
+ set_printk_time_clock(tsc_clock);
}
/* Do some early cpuid on the boot CPU to get some parameter that are
--
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