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,URIBL_BLOCKED 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 079AEC433E0 for ; Mon, 4 Jan 2021 21:02:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA791216C4 for ; Mon, 4 Jan 2021 21:02:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726168AbhADVCZ convert rfc822-to-8bit (ORCPT ); Mon, 4 Jan 2021 16:02:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:37484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726074AbhADVCY (ORCPT ); Mon, 4 Jan 2021 16:02:24 -0500 Received: by mail.kernel.org (Postfix) with ESMTPS id 67146216C4 for ; Mon, 4 Jan 2021 21:01:44 +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: Mon, 04 Jan 2021 21:01:44 +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: currojerez@riseup.net 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: 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 Francisco Jerez (currojerez@riseup.net) changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |currojerez@riseup.net --- Comment #5 from Francisco Jerez (currojerez@riseup.net) --- O_o, that's really weird. I guess this could also be some sort of electromagnetic interference (E.g. with your soundcard? Does the problem occur with the loudspeakers turned off?), or an issue with your PSU. The apparent frequency dropping below scaling_min_freq might be an artifact of how the busy frequency of a CPU thread is calculated: It should approximate the ratio of executed clock cycles to the time it spent in C0 state, which can deviate from its actual working frequency if the processor enters and exits some C1+ state repeatedly since the transition may have some significant latency. According to your turbostat log the CPU cores that report a busy frequency below scaling_min_freq seem to be handling quite a few interrupts which is consistent with that explanation. It doesn't necessarily indicate a power management bug. Does disabling some specific idle state (e.g via /sys/devices/system/cpu/cpu*/cpuidle/state*/disable) have any effect on the noise? -- You may reply to this email to add a comment. You are receiving this mail because: You are the assignee for the bug.