29 lines
818 B
Diff
29 lines
818 B
Diff
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Arjan van de Ven <arjan@linux.intel.com>
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Date: Wed, 11 Feb 2015 17:28:14 -0600
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Subject: [PATCH] smpboot: reuse timer calibration
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NO point recalibrating for known-constant tsc ...
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saves 200ms+ of boot time.
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---
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arch/x86/kernel/tsc.c | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
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index 7e322e2daaf5..bb2c9b5eed71 100644
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--- a/arch/x86/kernel/tsc.c
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+++ b/arch/x86/kernel/tsc.c
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@@ -1528,6 +1528,9 @@ unsigned long calibrate_delay_is_known(void)
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if (!constant_tsc || !mask)
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return 0;
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+ if (cpu != 0)
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+ return cpu_data(0).loops_per_jiffy;
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+
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sibling = cpumask_any_but(mask, cpu);
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if (sibling < nr_cpu_ids)
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return cpu_data(sibling).loops_per_jiffy;
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--
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https://clearlinux.org
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