From 2b35fd5f7f5f3286271ef5c513bd2d1aeaa7f0c1 Mon Sep 17 00:00:00 2001
From: Alok Kataria <akataria@vmware.com>
Date: Fri, 20 Jun 2008 15:06:33 -0700
Subject: [PATCH] --- yaml --- r: 99591 b: refs/heads/master c:
 3da757daf86e498872855f0b5e101f763ba79499 h: refs/heads/master i:   99589:
 ba1e8e0d901e00bea7f37959a4544b419368e5a2   99587:
 5f1f603173355315089698e81981c0b8912a3c97   99583:
 1dde88279ddcb6aa6e66d3a88415a35a05938c81 v: v3

---
 [refs]                          |  2 +-
 trunk/arch/x86/kernel/time_64.c |  2 ++
 trunk/arch/x86/kernel/tsc_32.c  |  5 +++++
 trunk/include/linux/delay.h     |  1 +
 trunk/init/calibrate.c          | 36 +++++++++++++++++----------------
 5 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/[refs] b/[refs]
index 8f1cb43a8ef0..3f86781fb388 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e01b70ef3eb3080fecc35e15f68cd274c0a48163
+refs/heads/master: 3da757daf86e498872855f0b5e101f763ba79499
diff --git a/trunk/arch/x86/kernel/time_64.c b/trunk/arch/x86/kernel/time_64.c
index c737849e2ef7..12b4a71bd074 100644
--- a/trunk/arch/x86/kernel/time_64.c
+++ b/trunk/arch/x86/kernel/time_64.c
@@ -123,6 +123,8 @@ void __init time_init(void)
 		(boot_cpu_data.x86_vendor == X86_VENDOR_AMD))
 		cpu_khz = calculate_cpu_khz();
 
+	lpj_tsc = ((unsigned long)tsc_khz * 1000)/HZ;
+
 	if (unsynchronized_tsc())
 		mark_tsc_unstable("TSCs unsynchronized");
 
diff --git a/trunk/arch/x86/kernel/tsc_32.c b/trunk/arch/x86/kernel/tsc_32.c
index 068759db63dd..be729035b30b 100644
--- a/trunk/arch/x86/kernel/tsc_32.c
+++ b/trunk/arch/x86/kernel/tsc_32.c
@@ -401,6 +401,7 @@ static inline void check_geode_tsc_reliable(void) { }
 void __init tsc_init(void)
 {
 	int cpu;
+	u64 lpj;
 
 	if (!cpu_has_tsc || tsc_disabled) {
 		/* Disable the TSC in case of !cpu_has_tsc */
@@ -421,6 +422,10 @@ void __init tsc_init(void)
 		return;
 	}
 
+	lpj = ((u64)tsc_khz * 1000);
+	do_div(lpj, HZ);
+	lpj_tsc = lpj;
+
 	printk("Detected %lu.%03lu MHz processor.\n",
 				(unsigned long)cpu_khz / 1000,
 				(unsigned long)cpu_khz % 1000);
diff --git a/trunk/include/linux/delay.h b/trunk/include/linux/delay.h
index 54552d21296e..01aec60590ab 100644
--- a/trunk/include/linux/delay.h
+++ b/trunk/include/linux/delay.h
@@ -41,6 +41,7 @@ static inline void ndelay(unsigned long x)
 #define ndelay(x) ndelay(x)
 #endif
 
+extern unsigned long lpj_tsc;
 void calibrate_delay(void);
 void msleep(unsigned int msecs);
 unsigned long msleep_interruptible(unsigned int msecs);
diff --git a/trunk/init/calibrate.c b/trunk/init/calibrate.c
index ecb3822d4f70..86286974dada 100644
--- a/trunk/init/calibrate.c
+++ b/trunk/init/calibrate.c
@@ -8,7 +8,9 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/timex.h>
+#include <linux/smp.h>
 
+unsigned long lpj_tsc;
 unsigned long preset_lpj;
 static int __init lpj_setup(char *str)
 {
@@ -108,6 +110,10 @@ static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;}
  * This is the number of bits of precision for the loops_per_jiffy.  Each
  * bit takes on average 1.5/HZ seconds.  This (like the original) is a little
  * better than 1%
+ * For the boot cpu we can skip the delay calibration and assign it a value
+ * calculated based on the tsc frequency.
+ * For the rest of the CPUs we cannot assume that the tsc frequency is same as
+ * the cpu frequency, hence do the calibration for those.
  */
 #define LPS_PREC 8
 
@@ -118,20 +124,20 @@ void __cpuinit calibrate_delay(void)
 
 	if (preset_lpj) {
 		loops_per_jiffy = preset_lpj;
-		printk("Calibrating delay loop (skipped)... "
-			"%lu.%02lu BogoMIPS preset\n",
-			loops_per_jiffy/(500000/HZ),
-			(loops_per_jiffy/(5000/HZ)) % 100);
+		printk(KERN_INFO
+			"Calibrating delay loop (skipped) preset value.. ");
+	} else if ((smp_processor_id() == 0) && lpj_tsc) {
+		loops_per_jiffy = lpj_tsc;
+		printk(KERN_INFO
+			"Calibrating delay loop (skipped), "
+			"using tsc calculated value.. ");
 	} else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) {
-		printk("Calibrating delay using timer specific routine.. ");
-		printk("%lu.%02lu BogoMIPS (lpj=%lu)\n",
-			loops_per_jiffy/(500000/HZ),
-			(loops_per_jiffy/(5000/HZ)) % 100,
-			loops_per_jiffy);
+		printk(KERN_INFO
+			"Calibrating delay using timer specific routine.. ");
 	} else {
 		loops_per_jiffy = (1<<12);
 
-		printk(KERN_DEBUG "Calibrating delay loop... ");
+		printk(KERN_INFO "Calibrating delay loop... ");
 		while ((loops_per_jiffy <<= 1) != 0) {
 			/* wait for "start of" clock tick */
 			ticks = jiffies;
@@ -161,12 +167,8 @@ void __cpuinit calibrate_delay(void)
 			if (jiffies != ticks)	/* longer than 1 tick */
 				loops_per_jiffy &= ~loopbit;
 		}
-
-		/* Round the value and print it */
-		printk("%lu.%02lu BogoMIPS (lpj=%lu)\n",
-			loops_per_jiffy/(500000/HZ),
-			(loops_per_jiffy/(5000/HZ)) % 100,
-			loops_per_jiffy);
 	}
-
+	printk(KERN_INFO "%lu.%02lu BogoMIPS (lpj=%lu)\n",
+			loops_per_jiffy/(500000/HZ),
+			(loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy);
 }