From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751968AbeDINDl (ORCPT ); Mon, 9 Apr 2018 09:03:41 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:48252 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751902AbeDINDj (ORCPT ); Mon, 9 Apr 2018 09:03:39 -0400 Subject: Re: [PATCH] perf list: Add s390 support for detailed/verbose pmu event description To: Mark Rutland , Thomas Richter Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, acme@kernel.org, brueckner@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com References: <20180409110015.20793-1-tmricht@linux.ibm.com> <20180409113732.6k3plpp6pqdcbzrh@lakrids.cambridge.arm.com> From: Thomas-Mich Richter Organization: IBM LTC Date: Mon, 9 Apr 2018 15:03:32 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180409113732.6k3plpp6pqdcbzrh@lakrids.cambridge.arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-IE Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18040913-0008-0000-0000-000004E85B51 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18040913-0009-0000-0000-00001E7B7FB5 Message-Id: <975962f2-3d85-2325-da31-b74951863cbe@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-09_06:,, 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=1011 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804090140 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/09/2018 01:37 PM, Mark Rutland wrote: > Hi, > > On Mon, Apr 09, 2018 at 01:00:15PM +0200, Thomas Richter wrote: >> From: Thomas Richter >> >> Perf list with flags -d and -v print a description (-d) or >> a very verbose explanation (-v) of CPU specific counter events. >> These descriptions are provided with the json files in >> directory pmu-events/arch/s390/*.json. >> >> Display of these descriptions on s390 requires the >> corresponding json files. >> >> On s390 this does not work because function is_pmu_core() >> does not detect the s390 directory name where the >> CPU specific events are listed. On x86 it is >> /sys/bus/event_source/devices/cpu >> whereas on s390 it is >> /sys/bus/event_source/devices/cpum_cf >> /sys/bus/event_source/devices/cpum_sf >> >> Fix this by adding s390 directory name testing to >> function is_pmu_core(). This is the same approach as taken for >> arm platform. > > I don't think this is quite right. > > On arm, we specifically look for PMU directories which have a > file called CPUs. e.g. > > /sys/bus/event_source/devices/arm_pmuv3/cpus > > ... where "arm_pmuv3" is the PMU name. > >> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c >> index 1111d5bf15ca..8675ddf558c6 100644 >> --- a/tools/perf/util/pmu.c >> +++ b/tools/perf/util/pmu.c >> @@ -562,6 +562,12 @@ static int is_pmu_core(const char *name) >> if (stat(path, &st) == 0) >> return 1; >> >> + /* Look for cpu sysfs (specific to s390) */ >> + scnprintf(path, PATH_MAX, "%s/bus/event_source/devices/%s", >> + sysfs, name); >> + if (stat(path, &st) == 0) >> + return 1; > > IIUC here we return true if the PMU has a sysfs directory, but all PMUs > (including uncore PMUs) should have such a directory, so this will make > is_pmu_core() always return true. > > Can you match the "cpum_" prefix specifically, instead? > > Thanks, > Mark. > I am sorry, I don't follow you. When I look at the code function sequence perf_pmu__scan() +---> pmu_read_sysfs() This functions scans directory /sys/bus/event_source/devices/ and calls for each entry in this directory. For s390 these entries exist: cpum_sf cpum_cf tracepoint and software +---> perf_pmu__find(); +---> pmu_lookup() +---> pmu_format() Looks for file /sys/bus/event_source/devices/cpum_cf/format/event and parses its contents. This returns 0 on s390. +---> pmu_type() Looks for file /sys/bus/event_source/devices/cpum_cf/type and and parses its contents. This returns 0 on s390. +---> pmu_aliases() Looks for directory /sys/bus/event_source/devices/cpum_cf/events and reads out every entry name which is treated as a event name and added to the list of PMU-Aliases together with the file contents. For example /sys/bus/event_source/devices/cpum_cf/events/SF_CYCLES_BASIC with the file contents event=0xb0000. This is the raw event number. +----> pmu_aliases_parse() + perf_pmu__new_alias() Check and add alias name to a list. +---> pmu_cpumask() This tests for files /sys/bus/event_source/devices/cpum_cf/cpus or /sys/bus/event_source/devices/cpum_cf/cpumask which do not exist on s390. +---> pmu_add_cpu_aliases() adds the list of aliases such as cpum_sf/SF_CYCLES_BASIC/ to the global list of aliases. But ths happens only when +---> is_pmu_core() function returns true. And for s390 it needs to test for /sys/bus/event_source/devices/cpum_sf/ and /sys/bus/event_source/devices/cpum_cf/ directories. These directories are used to read the alias names in function pmu_aliases() above. Maybe I misunderstand this whole scheme, but with this patch the perf list commands works... -- Thomas Richter, Dept 3303, IBM LTC Boeblingen Germany -- Vorsitzende des Aufsichtsrats: Martina Koederitz Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294