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,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 3CBAAC3F2CD for ; Thu, 5 Mar 2020 05:07:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1CBA9208CD for ; Thu, 5 Mar 2020 05:07:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725930AbgCEFHA (ORCPT ); Thu, 5 Mar 2020 00:07:00 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:49438 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725208AbgCEFG7 (ORCPT ); Thu, 5 Mar 2020 00:06:59 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0254xpHa054385 for ; Thu, 5 Mar 2020 00:06:58 -0500 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2yj6nk1xe9-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 05 Mar 2020 00:06:58 -0500 Received: from localhost by e06smtp02.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) Thu, 5 Mar 2020 05:06:50 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 02556ma238338688 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 5 Mar 2020 05:06:48 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A000EA4051; Thu, 5 Mar 2020 05:06:48 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5BD0DA4053; Thu, 5 Mar 2020 05:06:41 +0000 (GMT) Received: from [9.199.61.135] (unknown [9.199.61.135]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 5 Mar 2020 05:06:40 +0000 (GMT) Subject: Re: [RFC 00/11] perf: Enhancing perf to export processor hazard information To: Andi Kleen Cc: Peter Zijlstra , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, eranian@google.com, mpe@ellerman.id.au, paulus@samba.org, mingo@redhat.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org, adrian.hunter@intel.com, kan.liang@linux.intel.com, alexey.budankov@linux.intel.com, yao.jin@linux.intel.com, robert.richter@amd.com, kim.phillips@amd.com, maddy@linux.ibm.com, Ravi Bangoria References: <20200302052355.36365-1-ravi.bangoria@linux.ibm.com> <20200302101332.GS18400@hirez.programming.kicks-ass.net> <20200303013329.GB1319864@tassilo.jf.intel.com> From: Ravi Bangoria Date: Thu, 5 Mar 2020 10:36:39 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200303013329.GB1319864@tassilo.jf.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 20030505-0008-0000-0000-00000359772C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20030505-0009-0000-0000-00004A7AACFD Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-03-04_10:2020-03-04,2020-03-04 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxlogscore=961 suspectscore=0 impostorscore=0 priorityscore=1501 bulkscore=0 phishscore=0 mlxscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2003050028 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andi, Sorry for being bit late. On 3/3/20 7:03 AM, Andi Kleen wrote: > On Mon, Mar 02, 2020 at 11:13:32AM +0100, Peter Zijlstra wrote: >> On Mon, Mar 02, 2020 at 10:53:44AM +0530, Ravi Bangoria wrote: >>> Modern processors export such hazard data in Performance >>> Monitoring Unit (PMU) registers. Ex, 'Sampled Instruction Event >>> Register' on IBM PowerPC[1][2] and 'Instruction-Based Sampling' on >>> AMD[3] provides similar information. >>> >>> Implementation detail: >>> >>> A new sample_type called PERF_SAMPLE_PIPELINE_HAZ is introduced. >>> If it's set, kernel converts arch specific hazard information >>> into generic format: >>> >>> struct perf_pipeline_haz_data { >>> /* Instruction/Opcode type: Load, Store, Branch .... */ >>> __u8 itype; >>> /* Instruction Cache source */ >>> __u8 icache; >>> /* Instruction suffered hazard in pipeline stage */ >>> __u8 hazard_stage; >>> /* Hazard reason */ >>> __u8 hazard_reason; >>> /* Instruction suffered stall in pipeline stage */ >>> __u8 stall_stage; >>> /* Stall reason */ >>> __u8 stall_reason; >>> __u16 pad; >>> }; >> >> Kim, does this format indeed work for AMD IBS? > > Intel PEBS has a similar concept for annotation of memory accesses, > which is already exported through perf_mem_data_src. This is essentially > an extension. It would be better to have something unified here. > Right now it seems to duplicate at least part of the PEBS facility. IIUC there is a distinction from perf mem vs exposing the pipeline details. perf-mem/perf_mem_data_src is more of memory accesses profiling. And proposal here is to expose pipeline related details like stalls and latencies. Would prefer/suggest not to extend the current structure further to capture pipeline details. Ravi