From a5232cc4fbb594c213eff4844952cdcb4bd5f95a Mon Sep 17 00:00:00 2001
From: Alexander Motin <mav@FreeBSD.org>
Date: Sun, 28 Jan 2018 18:18:03 +0000
Subject: [PATCH] Assume Always Running APIC Timer for AMD CPU families >=
 0x12.

Fallback to HPET may cause locks congestions on many-core systems.
This change replicates Linux behavior.

MFC after:	1 month
---
 sys/x86/x86/local_apic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c
index c9cc81f6ed2..3b8558b777e 100644
--- a/sys/x86/x86/local_apic.c
+++ b/sys/x86/x86/local_apic.c
@@ -526,6 +526,9 @@ native_lapic_init(vm_paddr_t addr)
 			do_cpuid(0x06, regs);
 			if ((regs[0] & CPUTPM1_ARAT) != 0)
 				arat = 1;
+		} else if (cpu_vendor_id == CPU_VENDOR_AMD &&
+		    CPUID_TO_FAMILY(cpu_id) >= 0x12) {
+			arat = 1;
 		}
 		bzero(&lapic_et, sizeof(lapic_et));
 		lapic_et.et_name = "LAPIC";