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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 085BBC43381 for ; Mon, 4 Mar 2019 04:07:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9F2A20863 for ; Mon, 4 Mar 2019 04:07:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726128AbfCDEG7 (ORCPT ); Sun, 3 Mar 2019 23:06:59 -0500 Received: from mga12.intel.com ([192.55.52.136]:2859 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725938AbfCDEG6 (ORCPT ); Sun, 3 Mar 2019 23:06:58 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Mar 2019 20:06:58 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,438,1544515200"; d="scan'208";a="279482274" Received: from spandruv-mobl3.jf.intel.com ([10.252.135.12]) by orsmga004.jf.intel.com with ESMTP; 03 Mar 2019 20:06:57 -0800 Message-ID: <47ce61b9df7701e047ef6f59afd54c854db8a538.camel@linux.intel.com> Subject: Re: [RFT][PATCH 0/2] cpufreq: intel_pstate: Handle _PPC updates on global turbo disable/enable From: Srinivas Pandruvada To: "Rafael J. Wysocki" Cc: "Rafael J. Wysocki" , Linux PM , LKML , Viresh Kumar , Chen Yu , Gabriele Mazzotta Date: Sun, 03 Mar 2019 20:06:57 -0800 In-Reply-To: References: <9956076.F4luUDm1Dq@aspire.rjw.lan> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-1.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2019-03-03 at 22:51 +0100, Rafael J. Wysocki wrote: > On Sun, Mar 3, 2019 at 10:20 PM Srinivas Pandruvada > wrote: > > > > On Sun, 2019-03-03 at 18:03 +0100, Rafael J. Wysocki wrote: > > > On Fri, Mar 1, 2019 at 6:39 PM Srinivas Pandruvada > > > wrote: > > > > > > > > On Fri, 2019-03-01 at 13:43 +0100, Rafael J. Wysocki wrote: > > > > > Hi All, > > > > > > > > > > This is how I would fix the issue reported in BZ 200759 (see > > > > > thisdev > > > > > patch series > > > > > from Yu too: > > > > > https://marc.info/?l=linux-pm&m=155137672924029&w=2) > > > > > . > > > > > > > > > > Patch [1/2] causes intel_pstate to update all policies if it > > > > > gets > > > > > a > > > > > _PPC change > > > > > notification and sees a global turbo disable/enable change. > > > > > > > > > > Patch [2/2] makes it update cpuinfo.max_freq for all policies > > > > > in > > > > > those cases. > > > > > > > > > > The patches here have not been tested yet, so testing would > > > > > be > > > > > much > > > > > appreciated. > > > > > > > > > > Of course, comments are welcome too! > > > > > > > > This is the only platform, someone reported such issue. > > > > > > I don't think this matters. > > > > > > First, it doesn't mean that no other problems have this problem. > > > > > > Second, the current handling of > > > MSR_IA32_MISC_ENABLE_TURBO_DISABLE > > > changes in intel_pstate is not sufficient if the changes is from > > > set > > > to unset anyway. > > > > Any platform with HWP, you can't even notify of this change. So any > > platform beyond SKL is not useful. > > Do you mean that HWP platforms don't supply _PPS (as a rule) and so > they don't send _PPC notifications? Is there anything they do > instead > of it? There are other methods like PL1 budget limit for such cases. FW can just change the config TDP level. > > That's fair enough, but the point is that the driver doesn'dev_t do > the > right thing even if the platform does send a _PPC notification. _PPC notification is to indicate levels in _PSS not to disable/enable turbo via IA32_MISC_*. The platform could have just set _PPC to 1 or to TAR-1. Here _PPC is sent for somthing more than just changing _PSS max level. Do we have bug in if _PPC just changes performance level? > > > Fixing is always good :-) > > Well, I can only agree with that ...