svn commit: r328514 - head/sys/x86/x86

[Alexander Motin]

Author: mav
Date: Sun Jan 28 18:18:03 2018
New Revision: 328514
URL: https://svnweb.freebsd.org/changeset/base/328514

Log:
  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

Modified:
  head/sys/x86/x86/local_apic.c

Modified: head/sys/x86/x86/local_apic.c
==============================================================================
--- head/sys/x86/x86/local_apic.c	Sun Jan 28 16:10:40 2018	(r328513)
+++ head/sys/x86/x86/local_apic.c	Sun Jan 28 18:18:03 2018	(r328514)
@@ -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";