1 files changed, 28 insertions, 0 deletions

diff --git a/patches/boot_time_opt/0108-smpboot-reuse-timer-calibration.patch b/patches/boot_time_opt/0108-smpboot-reuse-timer-calibration.patch
new file mode 100644
index 0000000..7dd298e
--- /dev/null
+++ b/patches/boot_time_opt/0108-smpboot-reuse-timer-calibration.patch
@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Arjan van de Ven <arjan@linux.intel.com>
+Date: Wed, 11 Feb 2015 17:28:14 -0600
+Subject: [PATCH] smpboot: reuse timer calibration
+
+NO point recalibrating for known-constant tsc ...
+saves 200ms+ of boot time.
+---
+ arch/x86/kernel/tsc.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
+index f70dffc2771f..dfb9f60554af 100644
+--- a/arch/x86/kernel/tsc.c
++++ b/arch/x86/kernel/tsc.c
+@@ -1546,6 +1546,9 @@ unsigned long calibrate_delay_is_known(void)
+        if (!constant_tsc || !mask)
+                return 0;
+ 
++       if (cpu != 0)
++               return cpu_data(0).loops_per_jiffy;
++
+        sibling = cpumask_any_but(mask, cpu);
+        if (sibling < nr_cpu_ids)
+                return cpu_data(sibling).loops_per_jiffy;
+-- 
+https://clearlinux.org
+