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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D99AC77B75 for ; Fri, 5 May 2023 22:51:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233517AbjEEWvk (ORCPT ); Fri, 5 May 2023 18:51:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230146AbjEEWvi (ORCPT ); Fri, 5 May 2023 18:51:38 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CF0A527E for ; Fri, 5 May 2023 15:51:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1683327097; x=1714863097; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=MLjQ9s2IYfiXfAtWDLAFaH8aZnQga2eI5OjXYPJ03XI=; b=WcZLCkkMESJ7xGpsmoF4wHXsKQozaeXJnj92J6k3mEXr+Xg6qjf9VPGB Zz4XhCT1lFDTVdD8BKyxtFWGRlaO0PWxhD9ruE27qJW/gxZm+azhSw1gd i3Wb3krd9Sl3lYB+qFeXlz2p6nl4Yo7YBU+3eK+sQTfbTX5tR+KwdODg2 YanNmEXLrD+Vcze1N9/Omiy8ZmmqzjkUvGOPpvp6M3N4zTUZa44odsmnn nYrDKG/TiTvesa3YAvv4H7uwlLZmSFAeMqfjQkXwq28AP9A+4LrfEn8tW Tbj48tHpcS+l2HxQXt1A89vPiA2wnRtKR2+SRkLvKjl290oa7VCB3GlVK w==; X-IronPort-AV: E=McAfee;i="6600,9927,10701"; a="352363531" X-IronPort-AV: E=Sophos;i="5.99,253,1677571200"; d="scan'208";a="352363531" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2023 15:51:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10701"; a="809444087" X-IronPort-AV: E=Sophos;i="5.99,253,1677571200"; d="scan'208";a="809444087" Received: from rmarepal-mobl3.amr.corp.intel.com (HELO [10.255.231.148]) ([10.255.231.148]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 May 2023 15:51:35 -0700 Message-ID: <4dd1d0f44fc4ae9d7b1b918fd4aeb52601669ace.camel@linux.intel.com> Subject: Re: [PATCH 5/6] sched/fair: Consider the idle state of the whole core for load balance From: Tim Chen To: Peter Zijlstra Cc: Ricardo Neri , Juri Lelli , Vincent Guittot , Ricardo Neri , "Ravi V . Shankar" , Ben Segall , Daniel Bristot de Oliveira , Dietmar Eggemann , Len Brown , Mel Gorman , "Rafael J . Wysocki" , Srinivas Pandruvada , Steven Rostedt , Valentin Schneider , Ionela Voinescu , x86@kernel.org, linux-kernel@vger.kernel.org, Shrikanth Hegde , Srikar Dronamraju , naveen.n.rao@linux.vnet.ibm.com, Yicong Yang , Barry Song Date: Fri, 05 May 2023 15:51:35 -0700 In-Reply-To: <20230505132347.GR83892@hirez.programming.kicks-ass.net> References: <849d3fee51d218de71ecc9d557667ff6b137ac2d.1683156492.git.tim.c.chen@linux.intel.com> <20230505132347.GR83892@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4 (3.44.4-2.fc36) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2023-05-05 at 15:23 +0200, Peter Zijlstra wrote: > On Thu, May 04, 2023 at 09:09:55AM -0700, Tim Chen wrote: >=20 > > @@ -10709,11 +10709,26 @@ static int should_we_balance(struct lb_env *e= nv) > > for_each_cpu_and(cpu, group_balance_mask(sg), env->cpus) { > > if (!idle_cpu(cpu)) > > continue; > > + else { > > + /* > > + * Don't balance to idle SMT in busy core right away when > > + * balancing cores, but remember the first idle SMT CPU for > > + * later consideration. Find CPU on an idle core first. > > + */ > > + if (!(env->sd->flags & SD_SHARE_CPUCAPACITY) && !is_core_idle(cpu))= { > > + if (idle_smt =3D=3D -1) > > + idle_smt =3D cpu; > > + continue; > > + } > > + } >=20 > Not only does that bust CodingStyle, it's also entirely daft. What > exactly is the purpose of that else statement? >=20 >=20 Yeah, that's a dumb "else" statement. Will remove that. Tim