From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04A1ACA9EAE for ; Tue, 29 Oct 2019 14:20:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1D1F20659 for ; Tue, 29 Oct 2019 14:20:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389150AbfJ2OUB (ORCPT ); Tue, 29 Oct 2019 10:20:01 -0400 Received: from mx3.molgen.mpg.de ([141.14.17.11]:36309 "EHLO mx1.molgen.mpg.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2388595AbfJ2OUB (ORCPT ); Tue, 29 Oct 2019 10:20:01 -0400 Received: from [10.17.212.211] (unknown [195.37.61.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: pmenzel) by mx.molgen.mpg.de (Postfix) with ESMTPSA id 04F0920225ADB; Tue, 29 Oct 2019 15:19:57 +0100 (CET) To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Arjan van de Ven Cc: x86@kernel.org, LKML From: Paul Menzel Subject: [PATCH] smpboot: reuse timer calibration Message-ID: Date: Tue, 29 Oct 2019 15:19:57 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arjan van de Ven Date: Wed, 11 Feb 2015 17:28:14 -0600 NO point recalibrating for known-constant tsc ... saves 200ms+ of boot time. Signed-off-by: Paul Menzel --- Arjan, can your Signed-off-by line be added? On what device, did you test this? This upstreams the patch from Clear Linux. https://github.com/clearlinux-pkgs/linux/blob/master/0108-smpboot-reuse-timer-calibration.patch arch/x86/kernel/tsc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index c59454c382fd..42b07ed467d2 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1525,6 +1525,9 @@ unsigned long calibrate_delay_is_known(void) if (!constant_tsc || !mask) return 0; + if (cpu != 0) + return cpu_data(0).loops_per_jiffy; + sibling = cpumask_any_but(mask, cpu); if (sibling < nr_cpu_ids) return cpu_data(sibling).loops_per_jiffy; -- 2.24.0.rc1