From patchwork Tue Apr 28 13:24:50 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Giovanni Gherdovich X-Patchwork-Id: 212204 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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 87F3BC83000 for ; Tue, 28 Apr 2020 13:25:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 732D3206E2 for ; Tue, 28 Apr 2020 13:25:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727122AbgD1NZQ (ORCPT ); Tue, 28 Apr 2020 09:25:16 -0400 Received: from mx2.suse.de ([195.135.220.15]:41830 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726940AbgD1NZM (ORCPT ); Tue, 28 Apr 2020 09:25:12 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id F1D36AD85; Tue, 28 Apr 2020 13:25:09 +0000 (UTC) From: Giovanni Gherdovich To: Srinivas Pandruvada , Thomas Gleixner , Ingo Molnar , Peter Zijlstra , Borislav Petkov , Len Brown , "Rafael J . Wysocki" Cc: x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Ricardo Neri , Linus Torvalds , Giovanni Gherdovich Subject: [PATCH 2/2] x86, sched: Bail out of frequency invariance if turbo frequency is unknown Date: Tue, 28 Apr 2020 15:24:50 +0200 Message-Id: <20200428132450.24901-3-ggherdovich@suse.cz> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200428132450.24901-1-ggherdovich@suse.cz> References: <20200428132450.24901-1-ggherdovich@suse.cz> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org There may be CPUs that support turbo boost but don't declare any turbo ratio, i.e. their MSR_TURBO_RATIO_LIMIT is all zeroes. In that condition scale-invariant calculations can't be performed. Signed-off-by: Giovanni Gherdovich Suggested-by: Ricardo Neri Fixes: 1567c3e3467c ("x86, sched: Add support for frequency invariance") --- arch/x86/kernel/smpboot.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 4718f29a3065..ab2a0df7d1fb 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1991,9 +1991,11 @@ static bool intel_set_max_freq_ratio(void) /* * Some hypervisors advertise X86_FEATURE_APERFMPERF * but then fill all MSR's with zeroes. + * Some CPUs have turbo boost but don't declare any turbo ratio + * in MSR_TURBO_RATIO_LIMIT. */ - if (!base_freq) { - pr_debug("Couldn't determine cpu base frequency, necessary for scale-invariant accounting.\n"); + if (!base_freq || !turbo_freq) { + pr_debug("Couldn't determine cpu base or turbo frequency, necessary for scale-invariant accounting.\n"); return false; }