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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 29A39C8300A for ; Thu, 30 Apr 2020 11:49:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D09220757 for ; Thu, 30 Apr 2020 11:49:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726930AbgD3Ltc (ORCPT ); Thu, 30 Apr 2020 07:49:32 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2134 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726127AbgD3Ltb (ORCPT ); Thu, 30 Apr 2020 07:49:31 -0400 Received: from lhreml724-chm.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id 950C4468E8A6D32915F1; Thu, 30 Apr 2020 12:49:30 +0100 (IST) Received: from [127.0.0.1] (10.47.0.178) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1913.5; Thu, 30 Apr 2020 12:49:29 +0100 Subject: Re: [PATCH] perf parse-events: Use strcmp to compare the PMU name To: Jiri Olsa CC: Jin Yao , , , , , , , , , , "irogers@google.com" References: <20200430003618.17002-1-yao.jin@linux.intel.com> <20200430084529.GC1681583@krava> <66b84e3f-f7d8-bb65-616e-d159a509a439@huawei.com> <20200430111551.GC1694693@krava> From: John Garry Message-ID: <0195184b-0b43-f2fd-8d80-3b70d3f5a950@huawei.com> Date: Thu, 30 Apr 2020 12:48:48 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20200430111551.GC1694693@krava> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.0.178] X-ClientProxiedBy: lhreml731-chm.china.huawei.com (10.201.108.82) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30/04/2020 12:15, Jiri Olsa wrote: + > On Thu, Apr 30, 2020 at 09:54:18AM +0100, John Garry wrote: >> On 30/04/2020 09:45, Jiri Olsa wrote: >>> On Thu, Apr 30, 2020 at 08:36:18AM +0800, Jin Yao wrote: >>>> A big uncore event group is split into multiple small groups which >>>> only include the uncore events from the same PMU. This has been >>>> supported in the commit 3cdc5c2cb924a ("perf parse-events: Handle >>>> uncore event aliases in small groups properly"). >>>> >>>> If the event's PMU name starts to repeat, it must be a new event. >>>> That can be used to distinguish the leader from other members. >>>> But now it only compares the pointer of pmu_name >>>> (leader->pmu_name == evsel->pmu_name). >>>> >>>> If we use "perf stat -M LLC_MISSES.PCIE_WRITE -a" on cascadelakex, >>>> the event list is: >>>> >>>> evsel->name evsel->pmu_name >>>> --------------------------------------------------------------- >>>> unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_4 (as leader) >>>> unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_2 >>>> unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_0 >>>> unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_5 >>>> unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_3 >>>> unc_iio_data_req_of_cpu.mem_write.part0 uncore_iio_1 >>>> unc_iio_data_req_of_cpu.mem_write.part1 uncore_iio_4 >>>> ...... >>>> >>>> For the event "unc_iio_data_req_of_cpu.mem_write.part1" with >>>> "uncore_iio_4", it should be the event from PMU "uncore_iio_4". >>>> It's not a new leader for this PMU. >>>> >>>> But if we use "(leader->pmu_name == evsel->pmu_name)", the check >>>> would be failed and the event is stored to leaders[] as a new >>>> PMU leader. >>>> >>>> So this patch uses strcmp to compare the PMU name between events. >>>> >>>> Fixes: 3cdc5c2cb924a ("perf parse-events: Handle uncore event aliases in small groups properly") >>>> Signed-off-by: Jin Yao >>> >>> looks good, any chance we could have automated test >>> for this uncore leader setup logic? like maybe the way >>> John did the pmu-events tests? like test will trigger >>> only when there's the pmu/events in the system >>> >>> Acked-by: Jiri Olsa >>> >>> thanks, >>> jirka >> >> Hi jirka, >> >> JFYI, this is effectively the same patch as I mentioned to you, which was a >> fix for the same WARN: >> >> https://lore.kernel.org/linux-arm-kernel/1587120084-18990-2-git-send-email-john.garry@huawei.com/ >> >> but I found that it "fixed" d4953f7ef1a2 ("perf parse-events: Fix 3 use >> after frees found with clang ASANutil/parse-events.c"), based on bisect >> breakage > > hum right.. sorry I did not recalled that, there's > also the warn removal in here, could you guys also > plz sync on the fixes clauses? I just thought that it fixes d4953f7ef1a2, as I found that the pointer equality fails from that commit. I assume the parse-events code was sound before then (in that regard). That's all I know :) Thanks! > > thanks, > jirka > >> >> cheers >> >>> >>> >>>> --- >>>> tools/perf/util/parse-events.c | 5 ++--- >>>> 1 file changed, 2 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c >>>> index 10107747b361..786eddb6a097 100644 >>>> --- a/tools/perf/util/parse-events.c >>>> +++ b/tools/perf/util/parse-events.c >>>> @@ -1629,12 +1629,11 @@ parse_events__set_leader_for_uncore_aliase(char *name, struct list_head *list, >>>> * event. That can be used to distinguish the leader from >>>> * other members, even they have the same event name. >>>> */ >>>> - if ((leader != evsel) && (leader->pmu_name == evsel->pmu_name)) { >>>> + if ((leader != evsel) && >>>> + !strcmp(leader->pmu_name, evsel->pmu_name)) { >>>> is_leader = false; >>>> continue; >>>> } >>>> - /* The name is always alias name */ >>>> - WARN_ON(strcmp(leader->name, evsel->name)); >>>> /* Store the leader event for each PMU */ >>>> leaders[nr_pmu++] = (uintptr_t) evsel; >>>> -- >>>> 2.17.1 >>>> >>> >>> . >>> >> > > . >