From patchwork Mon Jan 15 01:35:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: TimGuo X-Patchwork-Id: 10162909 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8B5EC602C2 for ; Mon, 15 Jan 2018 01:36:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 764A128946 for ; Mon, 15 Jan 2018 01:36:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6979A28956; Mon, 15 Jan 2018 01:36:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 54B8928946 for ; Mon, 15 Jan 2018 01:36:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752691AbeAOBgp convert rfc822-to-8bit (ORCPT ); Sun, 14 Jan 2018 20:36:45 -0500 Received: from zxshcas2.zhaoxin.com ([180.169.121.92]:31777 "EHLO ZXSHCAS2.zhaoxin.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1752259AbeAOBgo (ORCPT ); Sun, 14 Jan 2018 20:36:44 -0500 Received: from zxbjmbx2.zhaoxin.com (10.29.252.164) by ZXSHCAS2.zhaoxin.com (10.28.252.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1261.35; Mon, 15 Jan 2018 09:36:17 +0800 Received: from timguo-System-Product-Name.zhaoxin.com (10.29.8.61) by zxbjmbx2.zhaoxin.com (10.29.252.164) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1261.35; Mon, 15 Jan 2018 09:36:16 +0800 From: TimGuo To: , , , , , , CC: , , , , TimGuo Subject: [PATCH] x86/centaur: Mark TSC invariant Date: Mon, 15 Jan 2018 09:35:45 +0800 Message-ID: <1515980145-3693-1-git-send-email-timguo@zhaoxin.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 X-Originating-IP: [10.29.8.61] X-ClientProxiedBy: zxbjmbx1.zhaoxin.com (10.29.252.163) To zxbjmbx2.zhaoxin.com (10.29.252.164) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Centaur CPU has a constant frequency TSC and that TSC does not stop in C-States. But because the flags are not set for that CPU, the TSC is treated as non constant frequency and assumed to stop in C-States, which makes it an unreliable and unusable clock source. Setting those flags tells the kernel that the TSC is usable, so it will select it over HPET. The effect of this is that reading time stamps (from kernel or userspace) will be faster and more efficient. Signed-off-by: TimGuo --- arch/x86/kernel/cpu/centaur.c | 4 ++++ drivers/acpi/processor_idle.c | 1 + 2 files changed, 5 insertions(+) -- 1.9.1 保密声明： 本邮件含有保密或专有信息，仅供指定收件人使用。严禁对本邮件或其内容做任何未经授权的查阅、使用、复制或转发。 CONFIDENTIAL NOTE: This email contains confidential or legally privileged information and is for the sole use of its intended recipient. Any unauthorized review, use, copying or forwarding of this email or the content of this email is strictly prohibited. diff --git a/arch/x86/kernel/cpu/centaur.c b/arch/x86/kernel/cpu/centaur.c index 68bc6d9..c578cd2 100644 --- a/arch/x86/kernel/cpu/centaur.c +++ b/arch/x86/kernel/cpu/centaur.c @@ -106,6 +106,10 @@ static void early_init_centaur(struct cpuinfo_x86 *c) #ifdef CONFIG_X86_64 set_cpu_cap(c, X86_FEATURE_SYSENTER32); #endif + if (c->x86_power & (1 << 8)) { + set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC); + set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC); + } } static void init_centaur(struct cpuinfo_x86 *c) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index d50a7b6..5f0071c 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -207,6 +207,7 @@ static void tsc_check_state(int state) switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_AMD: case X86_VENDOR_INTEL: + case X86_VENDOR_CENTAUR: /* * AMD Fam10h TSC will tick in all * C/P/S0/S1 states when this bit is set.