Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752243AbcJZFWD (ORCPT ); Wed, 26 Oct 2016 01:22:03 -0400 Received: from ex13-edg-ou-002.vmware.com ([208.91.0.190]:56160 "EHLO EX13-EDG-OU-002.vmware.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751810AbcJZFWB (ORCPT ); Wed, 26 Oct 2016 01:22:01 -0400 From: Alexey Makhalov To: , , , , , CC: , , , , , , Alexey Makhalov Subject: [PATCH 1/3] x86/vmware: Use tsc_khz value for calibrate_cpu() Date: Tue, 25 Oct 2016 22:20:36 -0700 Message-ID: <20161026052038.77042-2-amakhalov@vmware.com> X-Mailer: git-send-email 2.10.1 In-Reply-To: <20161026052038.77042-1-amakhalov@vmware.com> References: <20161026052038.77042-1-amakhalov@vmware.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1360 Lines: 40 After aa297292d708, there are separate native calibrations for cpu_khz and tsc_khz. The code sets x86_platform.calibrate_cpu to native_calibrate_cpu() which looks in cpuid leaf 0x16 or msrs for the cpu frequency. Since we keep the tsc_khz constant (even after vmotion), the cpu_khz and tsc_khz may start diverging. tsc_init() now does cpu_khz = x86_platform.calibrate_cpu(); tsc_khz = x86_platform.calibrate_tsc(); if (tsc_khz == 0) tsc_khz = cpu_khz; else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz) cpu_khz = tsc_khz; We want the cpu_khz and tsc_khz to be sync even if they diverge less then 10%. This patch resolves this issue by setting x86_platform.calibrate_cpu to vmware_get_tsc_khz(). Signed-off-by: Alexey Makhalov Acked-by: Alok N Kataria --- arch/x86/kernel/cpu/vmware.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index 4e34da4b..480790f 100644 --- a/arch/x86/kernel/cpu/vmware.c +++ b/arch/x86/kernel/cpu/vmware.c @@ -83,6 +83,7 @@ static void __init vmware_platform_setup(void) vmware_tsc_khz = tsc_khz; x86_platform.calibrate_tsc = vmware_get_tsc_khz; + x86_platform.calibrate_cpu = vmware_get_tsc_khz; #ifdef CONFIG_X86_LOCAL_APIC /* Skip lapic calibration since we know the bus frequency. */ -- 2.10.1