32 lines
952 B
Diff
32 lines
952 B
Diff
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From 283fcb879f66da9659f1983bcf173476bae9292b 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 114/126] smpboot: reuse timer calibration
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NO point recalibrating for known-constant tsc... saves 200ms+ of boot time.
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Author: Arjan van de Ven <arjan@linux.intel.com>
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Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
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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 ad2b925a808e..6aed4e79f290 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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@@ -1352,6 +1352,9 @@ unsigned long calibrate_delay_is_known(void)
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if (tsc_disabled || !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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2.15.0
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