1 files changed, 16 insertions, 1 deletions

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index b21ddecea943..ff7df439da6d 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -375,6 +375,7 @@ static void __devinit
 smp_callin (void)
 {
         int cpuid, phys_id, itc_master;
+        struct cpuinfo_ia64 *last_cpuinfo, *this_cpuinfo;
         extern void ia64_init_itm(void);
         extern volatile int time_keeper_id;
 
@@ -424,7 +425,21 @@ smp_callin (void)
          * Get our bogomips.
          */
         ia64_init_itm();
-        calibrate_delay();
+
+        /*
+         * Delay calibration can be skipped if new processor is identical to the
+         * previous processor.
+         */
+        last_cpuinfo = cpu_data(cpuid - 1);
+        this_cpuinfo = local_cpu_data;
+        if (last_cpuinfo->itc_freq != this_cpuinfo->itc_freq ||
+            last_cpuinfo->proc_freq != this_cpuinfo->proc_freq ||
+            last_cpuinfo->features != this_cpuinfo->features ||
+            last_cpuinfo->revision != this_cpuinfo->revision ||
+            last_cpuinfo->family != this_cpuinfo->family ||
+            last_cpuinfo->archrev != this_cpuinfo->archrev ||
+            last_cpuinfo->model != this_cpuinfo->model)
+                calibrate_delay();
         local_cpu_data->loops_per_jiffy = loops_per_jiffy;
 
 #ifdef CONFIG_IA32_SUPPORT