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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 28834C4321A for ; Fri, 28 Jun 2019 01:12:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E65B9208CB for ; Fri, 28 Jun 2019 01:12:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="qsU3sGgT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726672AbfF1BMW (ORCPT ); Thu, 27 Jun 2019 21:12:22 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:47442 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726595AbfF1BMW (ORCPT ); Thu, 27 Jun 2019 21:12:22 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5S18jeH107834; Fri, 28 Jun 2019 01:11:54 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=Fpj98R7YPFrsbU/peaxe9+0g0ucs7pEIaE9mZ7f1KFs=; b=qsU3sGgTRtm0+MhQnq8q0HfNsf/LNdBgWJ07izxP+vDNcK0mTVx63SCOXeT7wu/Z+UOm CoCTey1kATTT04ZlCbhHn9VOM9t5OSWcquRnlylPcZCfBBaLoJK7BU2b36zZ5O4mGdYH RYuTCTrxaEn9ksgSkUCYer6RJrhFyVifTlr/FqkvxmJOCI3CTlFEOK+ASmszIxcRJSDF abhw5mGFutwc7oUfA081dCsdMtj4toEL1VGmYFIwy0j/Qqzjys9JRW11mvanoz7PbZtY ovpZTt30VTE8Lj7/ZbOxhy7Udq7MqD/BQBZ/PFw5pdPA+BnJV1Gj+4Gcvs1y5Vpo7dIW TQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 2t9brtk317-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 28 Jun 2019 01:11:54 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5S1BZJj093558; Fri, 28 Jun 2019 01:11:54 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3030.oracle.com with ESMTP id 2t9acdj129-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 28 Jun 2019 01:11:53 +0000 Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x5S1Bq7A007346; Fri, 28 Jun 2019 01:11:52 GMT Received: from [10.132.91.175] (/10.132.91.175) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 27 Jun 2019 18:11:51 -0700 Subject: Re: [PATCH v3 6/7] x86/smpboot: introduce per-cpu variable for HT siblings To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com, steven.sistare@oracle.com, dhaval.giani@oracle.com, daniel.lezcano@linaro.org, vincent.guittot@linaro.org, viresh.kumar@linaro.org, tim.c.chen@linux.intel.com, mgorman@techsingularity.net References: <20190627012919.4341-1-subhra.mazumdar@oracle.com> <20190627012919.4341-7-subhra.mazumdar@oracle.com> From: Subhra Mazumdar Message-ID: Date: Thu, 27 Jun 2019 18:06:47 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9301 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906280004 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9301 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906280004 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/26/19 11:54 PM, Thomas Gleixner wrote: > On Thu, 27 Jun 2019, Thomas Gleixner wrote: > >> On Wed, 26 Jun 2019, subhra mazumdar wrote: >> >>> Introduce a per-cpu variable to keep the number of HT siblings of a cpu. >>> This will be used for quick lookup in select_idle_cpu to determine the >>> limits of search. >> Why? The number of siblings is constant at least today unless you play >> silly cpu hotplug games. A bit more justification for adding yet another >> random storage would be appreciated. >> >>> This patch does it only for x86. >> # grep 'This patch' Documentation/process/submitting-patches.rst >> >> IOW, we all know already that this is a patch and from the subject prefix >> and the diffstat it's pretty obvious that this is x86 only. >> >> So instead of documenting the obvious, please add proper context to justify >> the change. > Aside of that the right ordering is to introduce the default fallback in a > separate patch, which explains the reasoning and then in the next one add > the x86 optimized version. OK. I will also add the extra optimization for other architectures. Thanks, Subhra > > Thanks, > > tglx