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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 B17B5C282C8 for ; Mon, 28 Jan 2019 17:19:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7EDA0214DA for ; Mon, 28 Jan 2019 17:19:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548695984; bh=Dy79b9BOySQUAkmNiupOrcXUtTCXyfqV2T4UzczNN/M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=n6YCvjTm7S9ucKAKP/EUGtMt/ujWIn0kStXRg3Pxa7b1poti8LYgLb9gPRe4JTFpB 5C58sUcJYhG7vGXEteU9DrmjsqBAvi7b5XOUJzlKydFOTZjtlcdev8pvaqaChe0t9T ZF7Ny7ajVWBLDPqADJYmDsD6LprWLE0cC4+iWNa8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731847AbfA1RTn (ORCPT ); Mon, 28 Jan 2019 12:19:43 -0500 Received: from mail.kernel.org ([198.145.29.99]:41362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731044AbfA1RTl (ORCPT ); Mon, 28 Jan 2019 12:19:41 -0500 Received: from localhost (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CB37E20989; Mon, 28 Jan 2019 17:19:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548695981; bh=Dy79b9BOySQUAkmNiupOrcXUtTCXyfqV2T4UzczNN/M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rdTD9FpKOf+hv1LjRoX4+SOcV/z3UeUhqTtt1f8nPyhEtW/1C+FDHfoeRZp0lX1Uu v71bH15zJP9J2H6ozhI61PaHNbaNPqm61FvRbuolNNCnttvZos7SDZi3V2yH2RlFue En/cElPJ3Ap6xTwIucRmNMmk60aPWeEdoiJXrJ/I= Date: Mon, 28 Jan 2019 12:19:39 -0500 From: Sasha Levin To: Quentin Perret Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Peter Zijlstra , Linus Torvalds , Mike Galbraith , Thomas Gleixner , adharmap@codeaurora.org, chris.redpath@arm.com, currojerez@riseup.net, dietmar.eggemann@arm.com, edubezval@gmail.com, gregkh@linuxfoundation.org, javi.merino@kernel.org, joel@joelfernandes.org, juri.lelli@redhat.com, patrick.bellasi@arm.com, pkondeti@codeaurora.org, rjw@rjwysocki.net, skannan@codeaurora.org, smuckle@google.com, srinivas.pandruvada@linux.intel.com, thara.gopinath@linaro.org, tkjos@google.com, valentin.schneider@arm.com, vincent.guittot@linaro.org, viresh.kumar@linaro.org, Ingo Molnar Subject: Re: [PATCH AUTOSEL 4.20 163/304] sched/topology: Add lowest CPU asymmetry sched_domain level pointer Message-ID: <20190128171939.GC3973@sasha-vm> References: <20190128154341.47195-1-sashal@kernel.org> <20190128154341.47195-163-sashal@kernel.org> <20190128161415.4r4b2gq54o6qdrxa@queper01-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20190128161415.4r4b2gq54o6qdrxa@queper01-lin> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 28, 2019 at 04:14:17PM +0000, Quentin Perret wrote: >Hi Sasha, > >On Monday 28 Jan 2019 at 10:41:20 (-0500), Sasha Levin wrote: >> From: Quentin Perret >> >> [ Upstream commit 011b27bb5d3139e8b5fe9ceff1fc7f6dc3145071 ] >> >> Add another member to the family of per-cpu sched_domain shortcut >> pointers. This one, sd_asym_cpucapacity, points to the lowest level >> at which the SD_ASYM_CPUCAPACITY flag is set. While at it, rename the >> sd_asym shortcut to sd_asym_packing to avoid confusions. >> >> Generally speaking, the largest opportunity to save energy via >> scheduling comes from a smarter exploitation of heterogeneous platforms >> (i.e. big.LITTLE). Consequently, the sd_asym_cpucapacity shortcut will >> be used at first as the lowest domain where Energy-Aware Scheduling >> (EAS) should be applied. For example, it is possible to apply EAS within >> a socket on a multi-socket system, as long as each socket has an >> asymmetric topology. Energy-aware cross-sockets wake-up balancing will >> only happen when the system is over-utilized, or this_cpu and prev_cpu >> are in different sockets. > >Although I'm not really confident about the process for those AUTOSEL >patches, I think this one alone won't help anybody without the other ~10 >EAS patches. And I assume you definitely don't want to mark those as >stable, so I'm not sure if this one is a good candidate either. I'll drop it then, thanks for the heads-up. >On a side note, the best description I could find of AUTOSEL with a >5 min Google search is this: https://lwn.net/Articles/750057/ >Do you have any pointers to a doc where I can read up about AUTOSEL ? For written material, this is based on Julia Lawall's work: https://soarsmu.github.io/papers/icse12-patch.pdf . We did a talk last year which is more recent than the paper: https://www.youtube.com/watch?v=KWholDv6-Rw . -- Thanks, Sasha