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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 1F003C4CEC9 for ; Tue, 17 Sep 2019 14:57:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E4A8C21852 for ; Tue, 17 Sep 2019 14:57:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728837AbfIQO56 (ORCPT ); Tue, 17 Sep 2019 10:57:58 -0400 Received: from 19.mo7.mail-out.ovh.net ([178.33.251.118]:60273 "EHLO 19.mo7.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728722AbfIQO56 (ORCPT ); Tue, 17 Sep 2019 10:57:58 -0400 Received: from player772.ha.ovh.net (unknown [10.108.57.14]) by mo7.mail-out.ovh.net (Postfix) with ESMTP id A9CCC133215 for ; Tue, 17 Sep 2019 16:40:01 +0200 (CEST) Received: from qperret.net (115.ip-51-255-42.eu [51.255.42.115]) (Authenticated sender: qperret@qperret.net) by player772.ha.ovh.net (Postfix) with ESMTPSA id 6B8229E4787E; Tue, 17 Sep 2019 14:39:42 +0000 (UTC) Date: Tue, 17 Sep 2019 16:39:37 +0200 From: Quentin Perret To: Giovanni Gherdovich Cc: srinivas.pandruvada@linux.intel.com, tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, bp@suse.de, lenb@kernel.org, rjw@rjwysocki.net, x86@kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, mgorman@techsingularity.net, matt@codeblueprint.co.uk, viresh.kumar@linaro.org, juri.lelli@redhat.com, pjt@google.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com Subject: Re: [PATCH 1/2] x86,sched: Add support for frequency invariance Message-ID: <20190917143937.GA334@qperret.net> References: <20190909024216.5942-1-ggherdovich@suse.cz> <20190909024216.5942-2-ggherdovich@suse.cz> <20190914105708.GA12877@qperret.net> <1568730466.3329.4.camel@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1568730466.3329.4.camel@suse.cz> User-Agent: Mutt/1.9.4 (2018-02-28) X-Ovh-Tracer-Id: 17312118445391502229 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedufedrudeigdehvdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Tuesday 17 Sep 2019 at 16:27:46 (+0200), Giovanni Gherdovich wrote: > I'll check what's the cost of static_cpu_has() and if it's non-negligible I'll > do what you suggest (x86-specific version of arch_scale_freq_invariant(). In case this is indeed expensive to check, you could always add a static key, set at boot time, to optimize things a bit ... That might be worth it since this is called in latency-sensitive paths of the scheduler. Thanks, Quentin