smpboot: reuse timer calibration

NO point recalibrating for known-constant tsc ...
saves 200ms+ of boot time.

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 2e076a459a0c084aa279f32f3fc644604713e595..94bc1166476ed8d35dbcb9e97ed766f0c2dcf931 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1549,6 +1549,9 @@ 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;