From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven 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 7e322e2daaf5..bb2c9b5eed71 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1528,6 +1528,9 @@ 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