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=-0.9 required=3.0 tests=DKIM_SIGNED, MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID,URIBL_BLOCKED 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 7A943ECDFBB for ; Wed, 18 Jul 2018 10:51:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 325C220852 for ; Wed, 18 Jul 2018 10:51:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="hHc5N6SA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 325C220852 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729750AbeGRL2y (ORCPT ); Wed, 18 Jul 2018 07:28:54 -0400 Received: from mail-oi0-f65.google.com ([209.85.218.65]:33422 "EHLO mail-oi0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726968AbeGRL2y (ORCPT ); Wed, 18 Jul 2018 07:28:54 -0400 Received: by mail-oi0-f65.google.com with SMTP id l10-v6so7928291oii.0; Wed, 18 Jul 2018 03:51:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=GKQuPuTadR5YjT5DkpjNdD7WSwHDSVQy8MG0OdYR1b8=; b=hHc5N6SArKO6LjL08xV40AVchvuUSiDXr5PcYSA9nQ+i7IXygHhdXpleULauA848Db 2vhPcK1J5kXn7xrTTaNb+dg7f5LbQ4qdG//qQMhoRJIj2pHAi8bg1qGiiuJaMYjKe30z 2DsjOm5zjkEQi8Pxs1++awx4GeHpoq+lU9dGT2iQwvzGq4uerFPp/cVHpQZqU/Hh3h0V VoiyANNBhwxC5j075Vy7ggb47Wg6we8fcCNCG3EdK/Yo2wJlecy1gTlSVBLTw+byo+pA 9Xa8Kc9BoI8HrucrNi+hg5JqThoykA/3GvQjTzPURAC2BjywLVlifZ5UefW+QAgE9bsI QNgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=GKQuPuTadR5YjT5DkpjNdD7WSwHDSVQy8MG0OdYR1b8=; b=ODqnaQkTTkIEsOnHej0XXxfNZAegIKUJib8qtpdFiqb5pfc/tEbLCdLPtnqe0V0hwl Vw2EKAC4SzBC+61XSBMNCOec03oFcwT9qNd5H936s+LgfM3edBdU15jp/Z1zXiWZE/me ZfUVOgmixImNb2X/1YpwpJOX8Pv0Ef/30H0rzALZ4kRBfWpLoe8m4cub54VNOeSVfQHz 75nGuJa48hZr0fAGvojrxAKYgGIxNdslxx9iAP3a6AjKo1vNoFqqV51rGFw/cwYQWCjs n9JC7TRgXOGtYpRbZA8PKUnYDwZm/ZzX5GA/yZhBjHyzcqKh0gAM2pK/8O6JZG+UHjuB NDdQ== X-Gm-Message-State: AOUpUlHNzMxSYAUSlSmEOXXpWH8EtcXuslxKxwVYw+nkU95xOEHrx1A6 FhTvEQG6y8ePRyHddi1C9TM2giAKZEEAG4yzkQI= X-Google-Smtp-Source: AAOMgpfOr1U80/TVsK9f2tZ423oJA6axTFXyu6zq0ktZNR1L8PwuUiUmEohEQbR+QmqAaS/O30n9K/duaGOQMg4Vo00= X-Received: by 2002:aca:5b0b:: with SMTP id p11-v6mr6284642oib.116.1531911095042; Wed, 18 Jul 2018 03:51:35 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a9d:63d2:0:0:0:0:0 with HTTP; Wed, 18 Jul 2018 03:51:34 -0700 (PDT) In-Reply-To: <20180718104300.dwgbqbnllvhwzrea@suselix> References: <20180717065048.74mmgk4t5utjaa6a@suselix> <20180717140336.ayovaz4ksdlak6bb@suselix> <8115130.Fhkpr82c7G@aspire.rjw.lan> <2386802.jRaeHeNqoJ@aspire.rjw.lan> <20180718104300.dwgbqbnllvhwzrea@suselix> From: "Rafael J. Wysocki" Date: Wed, 18 Jul 2018 12:51:34 +0200 X-Google-Sender-Auth: 7N06t_PIqvmwo2Yxr7KrJvrL8qI Message-ID: Subject: Re: [PATCH] cpufreq: intel_pstate: Register when ACPI PCCH is present To: Andreas Herrmann Cc: "Rafael J. Wysocki" , Srinivas Pandruvada , Linux PM , "Rafael J. Wysocki" , Peter Zijlstra , Frederic Weisbecker , Viresh Kumar , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 18, 2018 at 12:43 PM, Andreas Herrmann wrote: > On Tue, Jul 17, 2018 at 08:06:54PM +0200, Rafael J. Wysocki wrote: >> From: Rafael J. Wysocki >> >> Currently, intel_pstate doesn't load if _PSS is not present on >> HP Proliant systems, because it expects the firmware to take over >> CPU performance scaling in that case. However, if ACPI PCCH is >> present, the firmware expects the kernel to use it for CPU >> performance scaling and the pcc-cpufreq driver is loaded for that. >> >> Unfortunately, the firmware interface used by that driver is not >> scalable for fundamental reasons, so pcc-cpufreq is way suboptimal >> on systems with more than just a few CPUs. In fact, it is better to >> avoid using it at all. >> >> For this reason, modify intel_pstate to look for ACPI PCCH if _PSS >> is not present and register if it is there. Also prevent the >> pcc-cpufreq driver from trying to initialize if intel_pstate has >> been registered already. >> >> Fixes: fbbcdc0744da (intel_pstate: skip the driver if ACPI has power mgmt option) >> Reported-by: Andreas Herrmann >> Reviewed-by: Andreas Herrmann >> Acked-by: Srinivas Pandruvada >> Signed-off-by: Rafael J. Wysocki >> --- >> >> This is a replacement for https://patchwork.kernel.org/patch/10530091/ >> >> In addition to the intel_pstate changes in the above, it also >> prevents pcc-cpufreq from trying to initialize (which will fail >> ultimately, but may confuse the firmware in the meantime). >> >> Andreas, please test this one and let me know if it still works for you. > > Done that (with system in "Dynamic Power Savings Mode"). It still > works and system was stable. Thanks! > FYI, as a sniff test I've run a kernbench test. I now repeat the test > with system switched to "OS control mode". Just in case -- if there > was interference with platform code while system was in "Dynamic Power > Savings Mode" (significantly affecting performance) I might spot it > this way. I'd rather not expect performance to be affected by this, but power very well may be affected. Anyway, good idea! Cheers, Rafael