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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 6B01FC2BC61 for ; Mon, 29 Oct 2018 12:18:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 26DDD20664 for ; Mon, 29 Oct 2018 12:18:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 26DDD20664 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729304AbeJ2VGn (ORCPT ); Mon, 29 Oct 2018 17:06:43 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:48044 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729203AbeJ2VGn (ORCPT ); Mon, 29 Oct 2018 17:06:43 -0400 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w9TCEAVB057867 for ; Mon, 29 Oct 2018 08:18:16 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ne1ewswqk-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 29 Oct 2018 08:18:15 -0400 Received: from localhost by e06smtp03.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) Mon, 29 Oct 2018 12:18:10 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w9TCI9Cj66650160 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 29 Oct 2018 12:18:09 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A229B11C054; Mon, 29 Oct 2018 12:18:09 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2A79F11C052; Mon, 29 Oct 2018 12:18:09 +0000 (GMT) Received: from oc3784624756.ibm.com (unknown [9.152.212.21]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 29 Oct 2018 12:18:09 +0000 (GMT) Subject: Re: [PATCH] perf/stat: Handle different PMU names with common prefix To: =?UTF-8?Q?S=c3=a9bastien_Boisvert?= , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, acme@kernel.org Cc: brueckner@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, kan.liang@linux.intel.com, stable@vger.kernel.org References: <20181023151616.78193-1-tmricht@linux.ibm.com> <7b3b23b7-1c73-66bf-611b-8dd9fb274694@gydle.com> From: Thomas-Mich Richter Organization: IBM Date: Mon, 29 Oct 2018 13:18:08 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <7b3b23b7-1c73-66bf-611b-8dd9fb274694@gydle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18102912-0012-0000-0000-000002BFA8B1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18102912-0013-0000-0000-000020F3C9FD Message-Id: <80512536-d668-489d-5f73-d7e4a4d54e2d@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-10-29_09:,, 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810290117 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/26/2018 05:04 PM, Sébastien Boisvert wrote: > On 2018-10-23 11:16 a.m., Thomas Richter wrote: >> On s390 the CPU Measurement Facility for counters now supports >> 2 PMUs named cpum_cf (CPU Measurement Facility for counters) and >> cpum_cf_diag (CPU Measurement Facility for diagnostic counters) >> for one and the same CPU. >> >> Running command >> >> [root@s35lp76 perf]# ./perf stat -e tx_c_tend \ >> -- ~/mytests/cf-tx-events 1 >> > > Is tx_c_tend related to these ? > > tx-abort OR cpu/tx-abort/ [Kernel PMU event] > tx-capacity OR cpu/tx-capacity/ [Kernel PMU event] > tx-commit OR cpu/tx-commit/ [Kernel PMU event] > tx-conflict OR cpu/tx-conflict/ [Kernel PMU event] > tx-start OR cpu/tx-start/ [Kernel PMU event] > > Yes, these are the transaction counters on intel platforms, tx_c_tend is a transaction counter for s390. >> Measuring transactions >> TX_C_TABORT_NO_SPECIAL: 0 expected:0 >> TX_C_TABORT_SPECIAL: 0 expected:0 >> TX_C_TEND: 1 expected:1 >> TX_NC_TABORT: 11 expected:11 >> TX_NC_TEND: 1 expected:1 >> >> Performance counter stats for '/root/mytests/cf-tx-events 1': >> >> 2 tx_c_tend >> >> 0.002120091 seconds time elapsed >> >> 0.000121000 seconds user >> 0.002127000 seconds sys >> >> [root@s35lp76 perf]# >> >> displays output which is unexpected (and wrong): >> >> 2 tx_c_tend >> >> The test program definitely triggers only one transaction, as shown >> in line 'TX_C_TEND: 1 expected:1'. > > OK, something is done twice in perf stat, but should be done once. > Correct >> >> This is caused by the following call sequence: >> >> pmu_lookup() scans and installs a PMU. >> +--> pmu_aliases() parses all aliases in directory >> ...//events/* which are file names. >> +--> pmu_aliases_parse() Read each file in directory and create >> an new alias entry. This is done with >> +--> perf_pmu__new_alias() and >> +--> __perf_pmu__new_alias() which also check for >> identical alias names. >> >> After pmu_aliases() returns, a complete list of event names >> for this pmu has been created. Now function >> >> pmu_add_cpu_aliases() is called to add the events listed in the json >> | files to the alias list of the cpu. >> +--> perf_pmu__find_map() Returns a pointer to the json events. >> >> Now function pmu_add_cpu_aliases() scans through all events listed >> in the JSON files for this CPU. > > Are these JSON files temporary in nature ? No they are not, they are part of the perf tool, directory [root@s35lp76 linux]# ls tools/perf/pmu-events/arch/s390/cf_z14/* tools/perf/pmu-events/arch/s390/cf_z14/basic.json tools/perf/pmu-events/arch/s390/cf_z14/crypto.json tools/perf/pmu-events/arch/s390/cf_z14/extended.json tools/perf/pmu-events/arch/s390/cf_z14/transaction.json [root@s35lp76 linux]# >> Each json event pmu name is compared with the current PMU being >> built up and if they mismatch, the json event is added to the >> current PMUs alias list. >> To avoid duplicate entries the following comparison is done: >> >> if (!is_arm_pmu_core(name)) { >> pname = pe->pmu ? pe->pmu : "cpu"; >> if (strncmp(pname, name, strlen(pname))) >> continue; >> } > > Is this the test to know whether a PMU event must be added or not ? Correct. > >> >> The culprit is the strncmp() function. >> >> Using current s390 PMU naming, the first PMU is 'cpum_cf' >> and a long list of events is added, among them 'tx_c_tend' >> >> When the second PMU named 'cpum_cf_diag' is added, only one event >> named 'CF_DIAG' is added by the pmu_aliases() function. >> >> Now function pmu_add_cpu_aliases() is invoked for PMU 'cpum_cf_diag'. >> Since the CPUID string is the same for both PMUs, json file events >> for PMU named 'cpum_cf' are added to the PMU 'cpm_cf_diag' >> >> This happens because the strncmp() actually compares: >>> strncmp("cpum_cf", "cpum_cf_diag", 6); > > I fail to see how these argument values can be generated by this code: > > pname = pe->pmu ? pe->pmu : "cpu"; > if (strncmp(pname, name, strlen(pname))) > > The 3rd argument is the length of the first argument, pname. > > With "cpum_cf", it should be 7, not 6. Yes, mistake on my side... but it is the same type of error , regardless if 6 or 7 characters are compared: strncmp("cpmu_cf", "cpum_cf_diag", 7) returns 0 when it should not. The device names of both PMUs are different. > > > >> >> The first parameter is the pmu name taken from the event in >> the json file. The second parameter is the pmu name of the PMU >> currently being built. >> They are different, but the length of the compare only tests the >> common prefix and this returns 0(true) when it should return false. >> > > The 6 comes from strlen(pname). In that case, it is neither the length of > "cpum_cf" (7) or "cpum_cf_diag" (12). Correct as said above, can not count to 7... > >> Now all events for PMU cpum_cf are added to the alias list for pmu >> cpum_cf_diag. >> >> Later on in function parse_events_add_pmu() the event 'tx_c_end' is >> searched in all available PMUs and found twice, adding it two >> times to the evsel_list global variable which is the root >> of all events. This results in a counter value of 2 instead >> of 1. > > The counter value of 2 is 1 + 1 since both PMU events 'tx_c_end' that > were added got a +1. Correct, the transaction counter is 2 becauses it was connected to PMUs, but only one has the counter. > >> >> Output with this patch: >> >> [root@s35lp76 perf]# ./perf stat -e tx_c_tend \ >> -- ~/mytests/cf-tx-events 1 >> Measuring transactions >> TX_C_TABORT_NO_SPECIAL: 0 expected:0 >> TX_C_TABORT_SPECIAL: 0 expected:0 >> TX_C_TEND: 1 expected:1 >> TX_NC_TABORT: 11 expected:11 >> TX_NC_TEND: 1 expected:1 >> >> Performance counter stats for '/root/mytests/cf-tx-events 1': >> >> 1 tx_c_tend >> > > OK, now that's 1, like in your expected test value: > > TX_C_TEND: 1 expected:1 > >> 0.001815365 seconds time elapsed >> >> 0.000123000 seconds user >> 0.001756000 seconds sys >> >> [root@s35lp76 perf]# >> >> Fixes: 292c34c10249 ("perf pmu: Fix core PMU alias list for X86 platform") >> Signed-off-by: Thomas Richter >> Reviewed-by: Hendrik Brueckner >> Cc: Kan Liang >> Cc: # 4.18+ >> --- >> tools/perf/util/pmu.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c >> index 7799788f662f..7e49baad304d 100644 >> --- a/tools/perf/util/pmu.c >> +++ b/tools/perf/util/pmu.c >> @@ -773,7 +773,7 @@ static void pmu_add_cpu_aliases(struct list_head *head, struct perf_pmu *pmu) >> >> if (!is_arm_pmu_core(name)) { >> pname = pe->pmu ? pe->pmu : "cpu"; >> - if (strncmp(pname, name, strlen(pname))) >> + if (strcmp(pname, name)) >> continue; >> } >> >> > -- Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany -- Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294