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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 616DDC31E49 for ; Wed, 19 Jun 2019 06:02:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 39AAF20665 for ; Wed, 19 Jun 2019 06:02:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730784AbfFSGCq (ORCPT ); Wed, 19 Jun 2019 02:02:46 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:22168 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725866AbfFSGCq (ORCPT ); Wed, 19 Jun 2019 02:02:46 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5J627wV124765 for ; Wed, 19 Jun 2019 02:02:44 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2t7ephhuq0-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 19 Jun 2019 02:02:44 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 19 Jun 2019 07:02:32 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5J62Ndg33882608 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 19 Jun 2019 06:02:23 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 44450A4055; Wed, 19 Jun 2019 06:02:31 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A1C66A4051; Wed, 19 Jun 2019 06:02:29 +0000 (GMT) Received: from [9.124.31.60] (unknown [9.124.31.60]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 19 Jun 2019 06:02:29 +0000 (GMT) From: Ravi Bangoria Subject: Re: [PATCH 4/5] Powerpc/hw-breakpoint: Optimize disable path To: Michael Neuling Cc: mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, npiggin@gmail.com, christophe.leroy@c-s.fr, naveen.n.rao@linux.vnet.ibm.com, Ravi Bangoria References: <20190618042732.5582-1-ravi.bangoria@linux.ibm.com> <20190618042732.5582-5-ravi.bangoria@linux.ibm.com> Date: Wed, 19 Jun 2019 11:32:28 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19061906-0016-0000-0000-0000028A5A0F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19061906-0017-0000-0000-000032E7AE7E Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-19_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=361 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906190049 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/18/19 11:45 AM, Michael Neuling wrote: > On Tue, 2019-06-18 at 09:57 +0530, Ravi Bangoria wrote: >> Directly setting dawr and dawrx with 0 should be enough to >> disable watchpoint. No need to reset individual bits in >> variable and then set in hw. > > This seems like a pointless optimisation to me. > > I'm all for adding more code/complexity if it buys us some performance, but I > can't imagine this is a fast path (nor have you stated any performance > benefits). This gets called from sched_switch. I expected the improvement when we switch from monitored process to non-monitored process. With such scenario, I tried to measure the difference in execution time of set_dawr but I don't see any improvement. So I'll drop the patch. 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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 AF29FC31E49 for ; Wed, 19 Jun 2019 06:04:46 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 05AC120679 for ; Wed, 19 Jun 2019 06:04:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 05AC120679 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 45TDtg4ZJ5zDqlD for ; Wed, 19 Jun 2019 16:04:43 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=ravi.bangoria@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 45TDrL5rGVzDqJ5 for ; Wed, 19 Jun 2019 16:02:41 +1000 (AEST) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5J62Cfc062280 for ; Wed, 19 Jun 2019 02:02:39 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2t7d0e5w4v-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 19 Jun 2019 02:02:39 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 19 Jun 2019 07:02:32 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5J62Ndg33882608 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 19 Jun 2019 06:02:23 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 44450A4055; Wed, 19 Jun 2019 06:02:31 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A1C66A4051; Wed, 19 Jun 2019 06:02:29 +0000 (GMT) Received: from [9.124.31.60] (unknown [9.124.31.60]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 19 Jun 2019 06:02:29 +0000 (GMT) From: Ravi Bangoria Subject: Re: [PATCH 4/5] Powerpc/hw-breakpoint: Optimize disable path To: Michael Neuling References: <20190618042732.5582-1-ravi.bangoria@linux.ibm.com> <20190618042732.5582-5-ravi.bangoria@linux.ibm.com> Date: Wed, 19 Jun 2019 11:32:28 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19061906-0016-0000-0000-0000028A5A0F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19061906-0017-0000-0000-000032E7AE7E Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-19_03:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=362 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906190049 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ravi Bangoria , linux-kernel@vger.kernel.org, npiggin@gmail.com, paulus@samba.org, naveen.n.rao@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 6/18/19 11:45 AM, Michael Neuling wrote: > On Tue, 2019-06-18 at 09:57 +0530, Ravi Bangoria wrote: >> Directly setting dawr and dawrx with 0 should be enough to >> disable watchpoint. No need to reset individual bits in >> variable and then set in hw. > > This seems like a pointless optimisation to me. > > I'm all for adding more code/complexity if it buys us some performance, but I > can't imagine this is a fast path (nor have you stated any performance > benefits). This gets called from sched_switch. I expected the improvement when we switch from monitored process to non-monitored process. With such scenario, I tried to measure the difference in execution time of set_dawr but I don't see any improvement. So I'll drop the patch.