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=-4.0 required=3.0 tests=BAYES_00,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 6E067C433E0 for ; Sun, 3 Jan 2021 06:45:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31A1B2078D for ; Sun, 3 Jan 2021 06:45:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725840AbhACGpm convert rfc822-to-8bit (ORCPT ); Sun, 3 Jan 2021 01:45:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:57880 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725294AbhACGpm (ORCPT ); Sun, 3 Jan 2021 01:45:42 -0500 Received: by mail.kernel.org (Postfix) with ESMTPS id 851072078E for ; Sun, 3 Jan 2021 06:45:01 +0000 (UTC) From: bugzilla-daemon@bugzilla.kernel.org To: linux-pm@vger.kernel.org Subject: [Bug 210993] Intel frequency scaling causes electrical noise on 10th gen CPUs Date: Sun, 03 Jan 2021 06:45:01 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Power Management X-Bugzilla-Component: cpufreq X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: enhancement X-Bugzilla-Who: rui.zhang@intel.com X-Bugzilla-Status: NEEDINFO X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: linux-pm@vger.kernel.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_status cc Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=210993 Zhang Rui (rui.zhang@intel.com) changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |NEEDINFO CC| |rui.zhang@intel.com --- Comment #2 from Zhang Rui (rui.zhang@intel.com) --- (In reply to Karol Herbst from comment #0) > One thing I noticed with my i7-10850H CPU is, that if there are cores with > huge differences in their frequencies (e.g. one at 900 MHz another at 4.9 > GHz) some electrical becomes noticable. > > The noise can be reduced by limiting the available range the CPUs frequency > can be scaled to. Sadly the scaling_min_freq property is ignored outright > and only matters as long as the CPU stays idle, but as long as one core gets > some load, another one drops below scaling_min_freq, so I couldn't test if > limiting the lower bound even helps. Usually, if we didn't take Pe into account, the CPU frequency should not drop below scaling_min_freq. This sounds like a bug to me. please give turbostat output when this happens. > > Putting one core at max load with stress -c 1 effectively eliminates all > noise. please give turbostat output when this happens. > > This issue is even more annoying on my laptop as it generally runs with the > fans turned off. > > intel_pstate is used in active mode, but putting it in passive mode, > disabling HWP or even using the ACPI freq scaling didn't really change > anything in this regard. The powersave governor and default > energy_performance_preference is used. > > Is there anything else which could be done to mitigate the problem? Just > putting a finger on the touchpad makes the noise quite noticeable as cores > get scaled to the max. > I'd prefer this is the fan noise rather than CPU electrical noise. -- You may reply to this email to add a comment. You are receiving this mail because: You are the assignee for the bug.