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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 0BC50C606BF for ; Mon, 8 Jul 2019 14:27:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DB2E120844 for ; Mon, 8 Jul 2019 14:27:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731763AbfGHO1p (ORCPT ); Mon, 8 Jul 2019 10:27:45 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:27640 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730062AbfGHO1p (ORCPT ); Mon, 8 Jul 2019 10:27:45 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x68ERKLD115629 for ; Mon, 8 Jul 2019 10:27:44 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tm60yvfds-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 08 Jul 2019 10:27:43 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 8 Jul 2019 15:27:41 +0100 Received: from b06avi18878370.portsmouth.uk.ibm.com (9.149.26.194) by e06smtp01.uk.ibm.com (192.168.101.131) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 8 Jul 2019 15:27:39 +0100 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x68ERcGF41550226 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 8 Jul 2019 14:27:38 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1C1D7A4054; Mon, 8 Jul 2019 14:27:38 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C7927A405B; Mon, 8 Jul 2019 14:27:36 +0000 (GMT) Received: from linux.vnet.ibm.com (unknown [9.126.150.29]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with SMTP; Mon, 8 Jul 2019 14:27:36 +0000 (GMT) Date: Mon, 8 Jul 2019 19:57:36 +0530 From: Srikar Dronamraju To: "Enrico Weigelt, metux IT consult" Cc: Markus Elfring , kernel-janitors@vger.kernel.org, Ingo Molnar , Peter Zijlstra , LKML Subject: Re: [PATCH] sched/topology: One function call less in build_group_from_child_sched_domain() Reply-To: Srikar Dronamraju References: <20190706172223.GA12680@linux.vnet.ibm.com> <65dedcbc-aefb-eb30-39e1-194248214369@metux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <65dedcbc-aefb-eb30-39e1-194248214369@metux.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-TM-AS-GCONF: 00 x-cbid: 19070814-4275-0000-0000-0000034A3964 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19070814-4276-0000-0000-0000385A6110 Message-Id: <20190708142736.GC10675@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-08_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=797 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907080180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Enrico Weigelt, metux IT consult [2019-07-08 11:38:58]: > > > > At runtime, Are we avoiding a function call? > > However I think we are avoiding a branch instead of a conditional, which may > > be beneficial. > > If you're assuming the compiler doesn't already optimize that (no idea > whether gcc really does that). > > @Markus: could you check what gcc is actually generating out of both the > old and your new version ? > > I had already tried looking at the object files both on X86 and PowerPc and in both cases (with and without patch) the generated code differs. > --mtx > > -- > Enrico Weigelt, metux IT consult > Free software and Linux embedded engineering > info@metux.net -- +49-151-27565287 > -- Thanks and Regards Srikar Dronamraju